This stock is on my M1 carbine. It is a type III LW marked in slingwell. Lumb Woodworking as a subcontractor provided replacement stocks during WWII. However, I have been unable to find this cartouche in my reference materials. I think that BA over IAB is Benecia Arsenal (not sure) and I don't recognize the initials IAB. Would appreciate a heads-up if you recognize it.