[JP Noonan]

The part number (901.xxx.xxx) is on the side or top I think. The one your talking about is on the bottom rib right? If it is "HAx xxx xxx" then it is the serial number. H=manual A=5 speed x xxx xxx= consecutive running manufacture number up to Oct '72

After Oct. '72 the HA are the same but the first "xx" is the day the next two "xx" are the month, and the last "x" is the year.

The info I have only states this for up to 74. I don't know (I doubt it) if the 75-76 changed the system though.