Its a pistol so I'm going to assume yes
No
The only pistols professional does not effect are the police pistol and That Gun! due to a bug.
1. It goes by weapon animation type, so yes to gunslinger.
2. It's not on the form list for laser commander, so as you said, no for that.
3. It is on the form list for The Professional. (I wonder why Josh didn't add That Gun to the list in one of the patches?)
-Gunny out.