gary tree,

Welcome to the forum.

What cartridge is your revolver chambered for and what's the barrel length?

I don't think you have a 1917. You likely have a 455 Mk II hand Ejector - 2nd Model.

The # in the yoke that you see is an assembly #. It's third location is the inside of the side plate.

See below for the locations of the matching serial # including the yoke:

Serial # locations: To confirm all parts are original, check for your 6 matching serial # locations for fixed sight pre war Hand Ejectors and all post war Hand Ejectors thru ~1956.
NOTE: Observing serial #s for accuracy or even existence, especially on penciled stocks, requires magnification, bright light, and an attitude that it is there!

1. Gun butt - or forestrap on I frames/single shots with grips that cover the butt

2. Barrel - bottom of barrel or in extractor shroud

3. Yoke - on rear face only visible thru a chamber with a flashlight

4. Extractor star - backside

5. Cylinder - rear face

6. Right stock only - on back; stamped, scratched or penciled depending on vintage and stock material. (except most target grips because individual fitting not required.)

__________________
Jim
S&WCA #819