Screw for 41 .22 short kit?

[gose]

I have this .22 short topend for a 41 and in the (non factory) box it came in, there was also a screw. Since I dont own a 41, I cant really tell if this is just a random screw, or something that actually goes with a 41/kit.
Any ideas?

 

[Jeff in Cincinnati]

Looks like the safety detent/plate (not sure the exact name) screw.