VZ 24 with a 1" brass disc in the butt stock

I have a nice VZ 24 with a 1" brass disc in the butt stock. At 12 o'clock it's stamped 2 ZN, at 6 o'clock it's stamped 364. Anyone know what this indicates?

I've also been told the sling is original. What would verify this?

On left side of receiver is stamped F, then maybe a griffin image, then 26, below it are 8517E 1 - any clues on these stamps?

Thanks, JoeMC9

PLEEEESE post photos!


Your "griffin" could be the skinny version of the Czech proof-mark lion.


But I can't see the marks clearly from here!

2 ZN 364 = 2nd Engineers Regiment, firearm no. 364

"26"?? Likely made in 1926.