Well I gave Marlin a call. The guy from Marlin said that firing pins are restricted and can only be sent to a gunsmith that has a FFL on file with them. Plus he said they only carry 1 type if firing pin and was not aware of a "pre" 1974 or "post 1974" designation on their firing pins. So, for right now, it looks like I'm back at square 1.
Should I just try a "post 1974" and hope for the best? Anyone have any luck with a later style firing pin? I heard they won't work but I also heard there are 2 types of firing pins and now Marlin is telling me there aren't.
I'm so confused! Can anyone shed some light on this?