I recently acquired a used/excellent .54 Plains pistol from a member here (thanks Joe!). The lock action seemed a little "gritty" so I took it off and polished off those little casting gates that were left and while I was at it, cut a couple coils (a little at a time) off the sear spring. Lubed everything back up and it is now very smooth, the sear is still positive but the trigger pull is a bit lighter. However, I did notice a small inlet and pin hole in the tumbler that looked like it was for a fly. The pistol has a simple trigger and doesn't need the fly; so my question is....Is this lock the same as used on the GPR with double set triggers, and did my lock originally have a fly? Thanks. Emery