Forget about what is in the yoke area. The only helpful number is the one on the butt. Please supply that one, making note of any letter(s) that precede(s) it.
If the gun is "early" - from before and until about 1956, the same number that is on the butt will show up on the rear face of the cylinder and on the bottom of the barrel (as well as a few other places that are more difficult to see).
Also - supply the exact caliber marking from the barrel.