The problem with evaluating a local 'smith is, HOW do you judge him?
By reputation?
I've seen local gunsmiths the locals thought was simple great, who were butchers.
By your personal experience with him?
I know a local gunsmith with a great reputation who I used for several projects after I retired and no longer had the equipment.
The first two jobs were acceptable.
The last was probably the absolute WORST case of gun butchering I saw in 30 years in the business.
All I can say is to check his reputation, and ask WHERE he learned the trade.
If he graduated from a REAL gunsmithing school like Colorado School of Trades, or Trinidad College, he "probably" knows his stuff.
If he's self taught, was a "military armorer", learned as an apprentice, learned from a correspondence course, or doesn't want to be upfront about where he learned, BE CAREFUL.
As for Colt revolvers:
The older Colt's like the Python and Detective Special are VERY complicated actions, with tiny working surfaces, and have a totally non-transparent method of operation.
What function a part "appears" to be doing isn't what it's really doing.
Each and every part does at LEAST two operations, and any change "here" has consequences way over "there" that aren't apparent.
In the old days, the Colt was the more or less standard Police revolver, and most gunsmiths HAD to know how they operated and how to repair them.
Those days are long gone, and all the old timers are gone with them.
Modern 'smiths know all about the simpler S&W and Ruger guns, but know nothing about Colt's.
This leads to big problems. A gunsmith has an ego just like everyone else.
Many figure "it's "just" another gun, I can fix it".
It isn't, and they can't.
Too many locals get in way over their heads when, unlike S&W and Ruger revolvers, things just don't make sense, and making a minor change causes MAJOR problems somewhere totally unrelated to what they THOUGHT was going on.
This is all a matter of just not realizing that the older Colt's are a relic from the 1890's, NOT a more modern or simpler design.
The are complicated, convoluted, and EACH AND EVERY part is totally hand fitted. There are NO "drop in" parts.
The situation is better with the later Colt designs like the Trooper Mark III.
In 1969, Colt actually pioneered the modern revolver with the Mark III design, and EVERY DA revolver made since, is basically a modification of Colt's ground breaking design.
In these later guns, parts are NOT individually filed and stoned to a perfect fit.
Instead the factory fitter pulls a part from a bin and test fits it.
If it doesn't fit, he pulls another part out of the bin.
This eliminated most of the expensive hand fitting labor and keeps the price down.
This is also why the Python is the only old style Colt left, and why it costs so much......Hand labor and fitting.
The problem with the Mark III and local gunsmiths, is also lack of knowledge.
Many just don't know that on the later Colt's you DO NOT "repair" the action, you REPLACE it.
Any defective or worn parts CANNOT be re-fitted or "repaired", they are simply replaced with new parts.
The problem is, few locals have a bin full of parts from which they can test fit until they get a fit.
Too many, not knowing any better, order a new part, and when it doesn't fit, they start stoning it to make it fit.
The altered part DOES fit, and the gun DOES work..... for a while.
When they stoned the part, they broke through the super thin case hardened surface, exposing soft metal. Very soon the exposed soft metal wear or deforms, and you have problems, sometimes a damaged gun.
Colt and a VERY few non-factory gunsmiths are qualified to work on the old style Colt's, and too many locals just don't have the knowledge for the newer models either.
To eliminate damaged guns, guns in for one problem that come back with OTHER problems, and guns that just don't get fixed, I recommend using KNOWN qualified repair services for all Colt's.
I also recommend using factory repair for most ANY gun.
With a factory or factory recommended gunsmith you are at least assured that they know WHAT to do, HOW to do it, and have the factory new parts to do it.
There are plenty of very good local gunsmiths, but remember that most of them are "General Practitioners".
The can do most gunsmithing operations, but some guns require a specialist.
Without KNOWING the level of skills and knowledge of a local, you have no way of knowing if he's qualified, and you can't trust his word..... Ego, remember.
As an example, last year an old customer wanted a S&W re-barreled.
He told me that the nearest gunsmith was in a town about 100 miles away from where he now lives.
He asked around about the local, and he has a very good rep locally.
He talked to the 'smith and he assured the man that he had all the skills and knowledge AND had all the correct "factory tooling" to do the job RIGHT.
He offered to do the job while the man waited, since he was from so far away.
The 'smith took the S&W into the shop, and a few minutes later the man asked to use the rest room.
As he walked through the shop, he saw the "gunsmith" with his valuable S&W locked up in an ordinary Sears shop vise and the "gunsmith" shoving a hammer handle through the frame, so as to twist the frame off.
The man, needless to say, started screaming to stop, took his S&W and sent it in to S&W for re-barreling.
You do the best you can with trusting locals
"Buyer beware" holds for gunsmiths too.
Since they don't have to have some sort of license or professional certification, ANY ONE can be a gunsmith.