Identifying year of O/B

[jwclbi]

I recently purchased a 40 yamaha for my whaler but after a bit of research I can't seem to find out what year it is. The tag on the bracket reads as follows.
Top line reads - YAMAHA 40HMO
second line reads - 6HS S 187875
Also this engine is says AUTOLUBE on cowl, not "oil injected" Ive never seen that before either.
After some searches im told the last letter in model # is the year. In this case O. On the yamaha chart to identify the year, O doesn't exist. Any thoughts? Thanks