There was a 1973 Marlin 336 which sold for $10k a couple of weeks ago. I suspect money laundering, personally.
Remington went bankrupt, Marlin closed, Ruger bought the gear… it’s a tide shift from the takeovers and gradual changes of Freedom/Cerberus in Marlin’s history, so some folks are trying to cash in on their old JM stamped Marlins. The premise is that the machines aren’t really even the same, any longer, so these Ruger made Marlins, regardless of quality, aren’t really Marlins yet… and some may never return, naturally.