Without seeing it, my reaction would be to steam out as mnay of the dents as possible (damp washcloth under an iron). If the stock has an original finish, it's probably lacquer and the steam will do half your finish removal. Go to wood with a fine sandpaper.
Out and out gouges are a tough nut. I've used tinted epoxies, would fillers, and so forth. In the balance I've probably had better luck with the (carefully) tinted plastics for the simple reason that they finish better than fillers. This is a pretty clever crown here and someone is likely to be able to improve on this advice.
At the tailend, wet the wood one last time to raise the grain, and do the finish-sanding with Pilkington's tinted oil (Brownell's) to fill pores and put some color in the wood. Top coat it with Permalyn, either hand rubbed or sprayed. There may still be some signs of the gouges, but that often adds character to an old gun, and we're in it for the learning process, right?
