FWIW up until a couple years ago I was doing repairs for a local gun shop. One of the other guys in the shop was repairing an old Marlin but I can't remember if it was a model 39 or a 39a. I think it was an older 39a. Marlin had changed the carrier to a newer style some time go. A working carrier of the older style was nowhere to be found and believe me, we looked for one for months. Apparently there are a good number of old Marlins out there in need of a new carrier. Anyway, one of the guys in the shop finally either repaired the old one or was able to modify the newer style carrier to work in the older rifle. I think he modified the new one. I'm sorry, I don't remember the details beyond this but unless you find a parts donor gun or someone has started to make an aftermarket replacement, I don't think you are going to find a working old style carrier from regular parts sources. Neither Gun Parts or Jack First had one at the time. Good Luck and sorry I couldn't be more help.