I have a Oliver 77 serial #4501 471 , spec # 77-0850 . Should be a 1954 but it has a super 77 frame. I have a couple casting numbers on the frame  MA586D, 1M500M and on the engine is 185220 then below that is MI. The serial plate is under the dash.Whats up why don&#039;t my numbers match? Thanks Mike:o