Remington also told me today that mine did not exist in their records either. I just located another 12ga Remington 1100 with L prefix then 00 and then 4 low digits for the serial number. They resumed stamping the date code on the barrel on 10/1/01. They continued to mark the date code on the end flap of the shipping box. (*) On 8/9/99, stopped stamping the barrels with the date code. One needs to be sure that the barrel is original to the gun before trusting the Barrel Code listing, above. Using these barrel codes to date a shotgun is somewhat unreliable, as shotgun barrels are often interchanged at random. Using barrel codes (such as those listed above) to date the manufacture are reliable on Remington rifles, as the company rarely changed barrels on a customer's rifle. The following letters correspond to the months of the yearī - L - A - C - K - P - O - W - D - E - R - Xġ - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 Remington's manufactured after 1921 have a code located on the left side of the barrel near the frame that identifies the year and month of manufacture. Here is some information that you can get from you serial number after 1921

Remington 1100 serial number codes