My older Gun Parts Corp (www.gunpartscorp.com
) catalog shows the springs at $5 plus s&h, and shows repro stocks for $109. Some other parts show as available, but the magazine tube is not one of them.
The problem often encountered, as here, is that restoring the gun will almost certainly cost a lot more than buying one, and they are not all that rare or expensive. If you have money in it, you would probably be better off to trade it off and find one in better condition. If it is an heirloom, just cleaning it up as a wall hanger won't deplete the pocketbook, where trying to restore it would.