The early "waffle top" 336s use the same inlet as the 36. They are a bit deeper top to bottom through the grip so a modern 336 stock will leave the lower tang hanging out anywhere from 1/16-3/16" proud of the wood.
Early model 336 stocks are unobtainium too as most all cracked due to the way they were inlet. If you get your hands on one that isn't cracked it'll be a miracle and you should take it off and relieve the square corners in the inleting ASAP. They apparently stood the early models up on end and cut the spring relief cut square, which ends up making one "ear" break off.
Later on when the changed the profile of the tang they changed the relief cut to a 3/8" radius and used an induction coil wrapped around the rear of the reciever to do the final fit, a woodburner effect if you will. The stocks were then numbered and sent along with the guns to be put on after the metal was finished.
When Remington took over they literally threw the induction coil setup away. The engineers claimed that they would get a much better and faster fit if they CNCed all the inleting, which is why the stocks fit like crap on the newer guns. I've literally seen 4 plastic shims at least double the thickness off a milkjug crammed into one stock from the factory to try and take the wobble out of it.
