I recently purchased a new (to me) 1980 240d 4spd. The PO told me the speedo reads 10 mph off. The part # on the speedo is 123 542 62 01 and it goes up to 85 mph. Can anybody tell me if this is the correct part# for my car? I suspect the error is from someone in the past swapping in a speedo from something with a different rear end ratio, maybe a NA 300d.