Im considering buying a marlin cowboy sn 99,121,xxx, (thats 99 million).. Does anyone have any idea of when this was made.. thanks dave..

It was made in 2001.

The rifle was manufactured as indicated in 2001, North Haven. The serial number doesn't give any indication on how many have been made. Marlin applied serial numbers in order of the rifle being manufactured regardless of what model. The serial number before yours may have been applied to a model 60 22 long rifle semi-auto and the one after might have been a model 336 30-30. Just depends on which rifle was coming off the line and getting proof loaded.

Hopefully you bought it and you're loving it!