Hi Rabbitz,
Welcome to ALR. Looks to be a well made gun, but I'm not sure that's a Siler lock. Looking at the ends of the 2 screws behind the cock on the Siler's I have, the upper screw is a little forward of the lower one. On the lock here, the upper screw is a little behind the lower one. The shape of the pan on this lock doesn't look like a Siler, nor does the frizzen spring or the foot of the frizzen, but I guess they could have been reworked.
Unless you find a name on the barrel or in the patchbox, etc. it will be hard to determine who built the gun. It looks like a nice one. Check the bore to make sure she's not loaded or some kid hasn't stuffed something down the barrel, then go shoot!
-Ron