The lever & stock don't necessarily need to be from an 1895 - any Marlin 336 straight lever and buttstock will do - but the built-up/curved lower receiver/tang also needs to be switched out for the one that's for a straight-gripped rifle.
There's no bending of existing tangs, etc - as the tang screw boss is cast in at a specific angle for the original stock config. Just pull off your buttstock & look at the lower tang from the side.
All the small parts on the lower unit can be moved from the old one to the straight one - but Marlin won't sell one to you(or anyone).
The best way to do it, would be to find someone with a straight gripped 336, who wants a pistol gripped model, and swap parts wholesale with them.
