Yeah, Ask them. Sure we can give you a some line.... but if you talk to the guy and ask pointed questions, without being a jerk of course, you can get a pretty good feel for the guy.
Me, I have spent the last 5+ years since A&P school working in Alaska to Africa and in VA & KY/IN on a wide variety of A/C from the standard cessna/Piper planes, Beech, Tripacers, Bell 206's, Astar 350's, Robbies and some on C208's, B100 C90 King Airs, DHC-6, Eclipse Jets. Not super familiar with some of the latter... Get me the manuals and I'll work on just about anything. I also know what I wouldn't work on and what is above my skill level. I'm not super skilled at sheet metal or doing composite repairs on a significant structure.
At one point or another it's as much a matter of how did manufacturer X decide to solve the problem as compared to Man. Y's solution. Yes if you get the guy that has 50 years experience working on Bonanza's he'll be able to to tell you all the idiosyncrasies of the aircraft, but you might have to travel awhile to get to that guy. Is it worth it to you?
Look around his hangar. How's the shop? Being tidy isn't the only thing that matters, but it helps. There are some guys that are really good wrenches that aren't organized. Ask other people around about the mechanic.