I have used the L&R Manton in a lefty rifle and it is a nice little small lock that should be able to be used on a pistol.
I have had a few problems with these little locks but nothing major. The thing I dislike the most ablout these locks is that the fly is located under the tumbler and has a tendency to fall out during assembly.
They way I solved that problem is to use a grease lube to help hold it place during the assembly process. I also dislike having to completely dissasemble the lock to fit and polish every surface to get them clean enough to have a smooth working lock. Once you get the lock cleaned up and polished they seem to function very fast though. With the improvements that Bob has mentioned they should be a nice little lock.