Here's my take on it.
If you want to be a PRO, go to one of the good attendance colleges or trade schools.
Taking correspondence courses will prepare you to be a hobbyist and nothing more.
Serving as an apprentice depends on whether your teacher is himself any good. You may learn from a great gunsmith/teacher, or you may learn from a gun hacker.
Without the knowledge you have NO way of really telling the difference.
Local reputation means NOTHING.
If you want to be a pro, DO NOT even think about opening a shop on your own until you've been in the business for years.
Price of equipment, and overhead is VERY expensive, and chances are in the high 90% that you'll bust out quickly.
Making a living wage without having the experience AND CONTACTS in the business as a start-up business is almost impossible.
Also remember: As a self-employed gunsmith you ARE NOT A GUNSMITH. You're a BUSINESSMAN who does some gunsmithing.
MOST of your day will be spent doing businessman work NOT gunsmithing work.
You'll be on the phone talking to customers and suppliers, and doing paperwork, mostly for State and Federal governments, that has nothing to do with gunsmithing.
Most of this paperwork will be of absolutely NO benefit to you or your business, it'll be for the benefit of various bureaucrats .
If you LUCKY, you'll get to spend an hour or so actually gunsmithing.
The best way to handle it, is to go to a big school with a national reputation, then go to work for established business as a hired hand.
First, you'll learn more practical skills in your first year than you did in school, and second, the owner will be the one doing all the paperwork while you put in 8 hours solid of real gunsmithing.
There are more employers of gunsmiths than most people think.
The US government employs gunsmiths in many federal agencies and departments, and even the military employ some civilians.
Many big companies that aren't gun companies employ gunsmiths for research and development.
Custom gun makers like Wilson employ gunsmiths as do ALL the gun companies.
Some companies use gunsmiths on the assembly line, and the better ones do actual customer repairs.
Many big police departments and federal law enforcement agencies employ gunsmiths as armorers.
So, go to a good attendance school, and when you start your last year, start looking for employment. Most of the good schools offer placement services, and a lot of potential
employers often visit looking for the better graduates.
By the time you graduate, you should have either 3-4 GOOD interviews lined up, or actually have a job offer.
Work for the other guy for some years to build up experience and contacts in the industry, and to get a feel for what kind of gunsmithing you want to do.
Save your money and start picking up the more expensive equipment and tooling.
THEN take the risk of starting up on your own.
And remember, No matter WHAT a new business is, or WHO's running it, MOST of them go bust within 2-3 years.