6.5 Jeffrey!
Sorry I'm a tyro with Marlin Guide guns. :oops:
Are Guide gun frames compatible with each other?
I happen to have a mod. 375 with 20" barrel which is a long term project for CAS long range shooting. One of the mods is to switch out the pistol grip stock for a straight grip. If our frames are compatible, would you like to make a swap? You pay shipping on your end and I'll pay mine. Straight up, straight across. :-)
My present buttstock has a rubber recoil pad, pistol grip cap and a swivel stud, if these make a difference.
Btw, I believe you'll also have to switch out your finger lever along with what's been already mentioned. :-)
Forgot to mention that the butt stock is in excellent condition. Only a few very small, almost unnoticeable blemishes from storage. If your's is comparable or close to it, that'll be good enough. :-)