I would fix the old gun its worth a million in memories alone....it want bring much if you sell it...charlie

That stock is beyond repair realistically. It has already been repaired once or twice before and has not held up.

AND, that stock is not original anyway. It was made sometime after the gun was made. And it has been poorly altered after that point too.
Putting any effort or expense into that piece of wood would be throwing good money away.

Regarding purchasing used stocks…. These guns were all hand fitted and have a lot of variation from gun to gun. You could purchase 12 stocks before you find one that is a proper fit. It is just the way that it is.
The basic piece of info you need to have is the frame size which will determine the width of the stock head. That will be what you need to match in order to find a stock that MAY be compatible.

When you take your gun for a ride on the tractor, you should let it ride on the seat, not tied to the plow.