Dating 112 Sixty Five

I originally posted this as part of another unrelated question, so apologies to any that may have already read this.
I've just become the proud owner of an old 112 SixtyFive. Not 100% certain of age but looking at the pots I think it could be '76. ( serial number is BN04504 and chassis number is 2275-65 EX if anyone can be more specific dating it?) It has the 12AX7 PI and silver badges and is in incredible cosmetic condition for it's age! Thanks

There are a few posts about using transformer codes and speaker codes (if original) to date the amp. Scan back or use the search. What I found was from those posts is that many of the trannies are Woodward-Schumacher and have a code like 606-740. 606 identifies the Woodward-Schumacher, 7 means 1977 (could also be 67 or 87), then 40 means the 40th week.