OUCH! What a bummer, I wonder what caused it? Do you think someone tried to pry a oiler out of the stock without removing the sling strap first? Even with the damaged stock and the mixed trigger housing and its parts its still a really nice carbine,plus you can always replace the parts with the right ones if it really bugs you.As far as the stock goes, If it were damaged during its service in the military I would consider leaving it as is.If you want to try repairing it, I suppose you could go to a woodworking place that sells wood and see about getting a scrap with would closely match the grain of the stock, straighten the edges of the damaged area and carefully fit a piece of wood into it and then refinish the area.You cant hurt it so you dont have anything to lose in that respect.
Congrats!
John