I want to check to see if the numbers are correct on my 880 and try to find out what year my 77 is. The 880 is a 1961 serial number 116 664 873 Spec number 48-0012. The numbers on the engine block above the starter are from top down 104 305A and what looks like an A stamped into the block. Second row 190320-NS with an S stamped into the block. Third row 7141 with an upside down F.
Now my 77 has no number plate on the dash, rivets broken I guess. The numbers on the motor above the starter are 185220B and second row IMI00B then behind these numbers vertical is 01_N not sure about the 3rd digit. I bought the 77 mid 80’s on a sale it was listed as a 77. The front frame appears to be from a super with the flat mounting plates and once when I bought some parts for the carb it matches the Super 77 carb ID.
One other question I have seen some people right about getting a build card. How would I do this for the 880? 
Thanks for your help
John Schoenauer