I'd wager those A7's were in service somewhere by the end of November '68. Those are all very "mainstream" Altec components, and at that exact point in history i don't think those components saw much in house shelf time at all once the glue was dry.

It's just my WAG after all, but there sure is a lot of that vintage Altec still in circulation today which seems to indicate that "product" was sellin just fine.