Help with identifying 12 bolt rear end

[jhvaughn]

I bought this rear end from a guy. Said it was a '70 but it's a 5 lug. So, I'm thinking it's a 71 or 72. Plan is to use it on my '60 C10. I've identified some markings, and believe it's a 3:73 (not 100% sure).

Here are some pics.





Reads: HA 09 22

How do I identify the exact year model? I would like to rebuild the rear brakes and assume I need the correct year for getting all new parts.

Any help you guys can provide will be GREATLY appreciated.

Thanks in advance,
Heath