Identify year of this KZ550 engine?

I'm looking at a 1981 KZ550, being sold as mostly stock, bike seems to be in good shape. Looking at pictures online, I'm not seeing any '81's that have this style case cover? Anything about these pictures indicate that this engine is anything other than a stock '81 KZ550?
thanks!

Ha! 12 minutes after posting this I heard from the owner, he was mistaken, it is an '83.
nonetheless, I'll leave this post up in case anyone spots anything I should be aware of.

Get the VIN and search, but 83 looks right. R

1983 Kz550A4 Standard Kz.
That is the last year of the standard in the U.S.
It is different from the other Kz550A models in that it uses the newer style motor and carbs.
That bike uses TK-26 CV carbs (similar to the TK26 CV carbs found on the Kz550H (gpz) models and Kz550M/F (shaft-drive Ltd.) models).
Internal motor parts are basically the same as the earlier Kz550A1-A3 motors, which are the same as the M and F Ltd models, except for the shaft drive.