As a rule the 1970's and early pre-safety 1980's guns. Over the years Marlin has gone back and forth on the stock design. All of them made since the 1990's are way too fat, as are some older versions. The 1970's guns used a forend that was much trimmer like the Winchester 94. On older guns some are trim, others fat. I haven't figured out any pattern. I have a 1958 336 that has the trim forend
