Your work on the P2K car does indeed look very nice.  I agree that the P2K models are generally very good. The UP A-50-17 car that this model is intended to depict has the extra row of vertical seam rivets that are characteristic of many UP boxcars (see attached).  Are you considering adding Archer rivets to address this?

No. As I mentioned, this is going to be a “mainline car,” which will likely always appear only in moving trains (to and from staging) in my layout operations. As such, I didn’t want to go terribly far in detailing.
There are Archer sets with the “double spacing” that could do these rivet rows; but they are black, so you’d have to figure out how to paint them and only them.

Tony