Welcome to THR Joe.
If memory serves me correctly, that is the serial number. As for age, you can check with a local gunsmith or store and see if they have one of those thick books of "gun values". There will be a listing for that gun somewhere in the book and it will offer a range of serial numbers that cover certain years. This will give you a rough idea of the gun's age.
If you need more specific info, try emailing Marlin but they may want a fee for any reasearch they do.
Good luck.