left hand remingtion 1100 20 ga

I just picked up a LH 20 ga 1100.I want to know what year it was made.I did a net search and think it was made in 1977.My sn# L512450x.My search said the x at the end of the sn ment made in 1977.This is a 26 in vent rib marked skeet.this gun looks new and the only defect is a few marks on the forarm,otherwise the wood is perfect.Thanks mark.