I have an early 2000's Marlin 336A buttplate that I would be happy to give you but it doesnt sound like it's what your're looking for. Have you tried Jack First Gun Parts?
Buy one from Brownells.They are oversize and are easy to file down to the correct size.
Its all right to be white!! Stupidity left unattended will run rampant Don't argue with stupid people, They will drag you down to their level and then win by experience