It sounds from that as if it is more of an aesthetic thing than a functional thing?
Correct. IMO, of course. Below is a picture of my 686s used in matches. The pre-lock gun on top is actually my backup.
The lock & MIM parts seem to get all the discussion, but if the gun's going to get shot a lot (i.e. be a match gun), there are other design elements I have stronger personal preference for, e.g. pinned front sight (the factory red ramp must go, IMO), frame mounted firing pin, new style cylinder release, and a non-pinned ejector. Only the 686-5 has all these without the lock (my backup 686 is a -5), so if I ever need to buy another 686, I'd have to wait for a -5, or just buy new.
One more word about a new S&W: While you'd avoid potentially buying someone else's problem, there's no guarantee a new gun will be perfect from the factory, either. S&W still makes a terrific revolver. Between design elements and modern CNC machinery, they are able to produce very accurate & reliable guns with much less hand fitting. The thing is, I'll occasionally read about a lemon that managed to get through their QA/QC. The good news is that S&W's customer service is very good, and any issues are quickly addressed once they are contacted.
Keep us posted. We'll expect a range report soon.