Mariner 60 E Japan built help in identifying year

[TNBOY]

Please help , I have a Mariner 60 hp 2 cylinder Japan built that I need identifying the year. I cannot find the letter in the right hand corner That would tell me the year I have been told it is a 1976 thru 1978 but I need to know for sure what it is. So far what I have is 60E 675 L 309763. I cannot get Reverse and have started to wonder if it was a model without one. I bought this from a guy who said he had replaced the lower seals and I believe he may not have put it back in right so I need the year to get a diagram of the assembly and procedure for removing the lower.

 

[haventaclue]

The number is putting it at '81. http://www.marineengine.com/parts/mariner-outboard-parts/60-2-cyl/675304181-and-up .It does have reverse,I think the guy didn't put it back together right.