I have a Stevens 77A 12 gauge pump and I was wondering if any one knows when these were manufactured? the barrel is marked on the left side:

STEVENS Savage Arms Corporation MODEL 77A
Chicopee Falls, Mass U.S.A

Right side is marked:

Proof Tested 12 Gauge
---- 2 3/4 Inch Chamber -----

Stock and forearm are wood and the forearm is round with grooves cut in it. It has a 27" barrel. Its a good shooter and in the cue to get refinished any info would be appreciated.