I quote from the Marlin FAQs:
2. Q) How can I get a product catalog or Owner's Manual?
To obtain a product catalog click here
To obtain an Owner's Manual
Please send your name and address to:
Marlin Services
P.O. Box 248
North Haven, CT 06473
Be sure to specify the model name and serial number of the specific firearms.
I wrote them a letter a while back asking about parts for my 1976 model 336. They sent me a xeroxed parts catalog for the rifle with shipping instructions, etc. I think they are more in tune with regular letters than e-mails or phone messages. It did take a while, though. Give them some time to snail-mail you the information you needed.
-WH-