Thank you for posting your numbers.
Could you please double check it,,,,,,is there a "0" after the UM ?
The reason I asked you was like you said it's a 1999 gun according to those numbers and what we have in our data base.
Puzzles me is the undrilled receiver. Another Mossberg mystery. ???
You could email ,,,,
Martinez, Norma
martinezn@mossberg.com
She will give you the exact born date.
Mossberg started serial numbers in 1968. You might want to email Mossberg and see if they can determine what year it is from any stampings. ????
Martinez, Norma
martinezn@mossberg.com
Also you can contact National Mossberg Collectors Association. That's run by Vic Havlin (636) 937-6401.