Rear axle verification help please

[the67Beast]

I wanted to see if any of you guys can help me verify my rear axle on my truck. It is a 67 C-10 with 6-lug wheels and the rear end is a 12-bolt GM with the following numbers cast into the differential case: D147 and NF3896838 and GM 56.

I have read thru some of the other rear end posts on here and according to what I have read I should have a 3:73 gear.

Stamp on the axle tube reads: HA 05 31 W

I think the "HA" means 3:73, but what does the rest mean??

Please forgive me as I am still fairly new to Chevy and C-10's.

Thanks!!!