Well Fellas,
Speaking of Glenfield / Marlin Model 30's, I've got an OLD one in .35 Remington with a 20 inch barrel and a 2/3 tube magazine (4 shots) that has a serial number prefixed with the letters "AC" followed by numbers in the 25000-30000 range. So Yep, they's been making model 30's awhile now ain't they?

Flower Child
P.S. I ain't even got an idea how old this one is but it has been in my family a LONG TIME. Maybe one of y'all can date the thing.