Help Identify 8 1/4 differential?

I have an 8 1/4 cone type shur grip complete rear end I bought on CL. The casting #'s on the case is #3723599, . I need to start buying parts for this unit and I want to make sure I am asking for the right stuff. In would like to buy a new back cover plate as the chrome aftermarket one does not fit with what I am building. Any help will be much appreciated!
TIA, Rat