I really like Derek at Sportsmans Guns and Ammo. I've been a customer of his for years and trust him with all of the firearms that i trust my life to for work. He's very knowledgeable about a variety of firearms and is a class three dealer and manufacturer of class two items too i think. He also has very good prices.
That being said, since he's a gun smith he is just like every other gun smith in the regards that he has a policy regarding customers overseeing his work. He even posts his policy on the wall and its something vaguely along these lines:
25 dollars an hour for me to work
35 dollars an hour for me to work if you watch
50 dollars an hour for me to work if you help
they can do it faster better and cheaper if you dont distract them with a bunch of questions and your breath on their shoulder.
I can understand your desire to look however. I remember bringing in a weapon once that required some hammering or something to be done, It was a stuck case or something. Anyhow i could hear him working on it in the back and it was all i could do to prevent myself from climbing over the counter to see what was going on.
In the long run its just best that you dont though.