Awesome!...Simply AWESOME!
I will have to open the book now and do some research.
Your backstrap looks like a Model 39-2, Is your gun a 14 shot double stack?
The "hole" hammer is from the original Model 39
Is your frame steel or aluminum and is it groove or check cut at the front & back or smooth?

Always wondered why S&W didnt offer wood grips for the 59 series or a barrel chambered for 30 Mauser.

Congrats on a rare and unusual find...Can you post more pics?
If you dont mind me asking...Where did you find it...?

NOT:..Just checked the SCSW 3rd edition, page 223 says "Unconfirmed report of at least one model 39 or 39-2 chambered for the .30 Luger cartridge...Nothing found about a 59 in 30 Luger.

You DEFINATELY should get it lettered!
NEED more Pics!