Rearend identification numbers

[Glow Worm]

Can anyone tell me what this is?
While verifying the rearend on my 73 'Cuda, I noticed numbers stenciled on the passenger side of the housing. The housing is a 2881489 but the stenciled number appears to be an upside down "7" with a line under it and then the numbers 328 which are right side up.
There was a tag in the console with 3.55 stamped on it, and the original owner siad nothing has been changed on the car I am assuming this is a 489 Sure Grip with 3:55 gears, but I'm puzzled by the stenciled numbers. Thank you for your help.

 

[Mopars & Missiles]

I think the 328 is the date code the 489 case was built. If so, this would be March 28th, 1973. What is the scheduled production date for your Cuda? Is it late April, early May of '73?

 

[DetMatt1]

The 328 could be the last 3 digits of the part number for the assembly. Do you have a build sheet for the car?

 

[Mopars & Missiles]

The 328 could be the last 3 digits of the part number for the assembly. Do you have a build sheet for the car?

Matt, it very well could be an assembly p/n, I'm really not sure. But the reason I suggested a date code is because my 70 Challenger has 9-12 ink stamped on the case and the SPD of the car is 9-17. So that led me to believe this may be a date code? Dunno for sure?

And then of course we are talking different years (70 vs 73), different models (Challenger vs Cuda), possibly different assembly plants (mine was Hamtramck vs whatever his is), etc, etc.

 

[Glow Worm]

Thanks for the information. I do have the Broadcast sheet and Broadcast IBM card. Neither one show anything that would match the stenciled numbers. The car is a 73.