Shiny Black Primer?

That is correct. We used DTM paint on some cabooses that we painted. It was a very ugly color brown. The railroad must have gotten a good deal on some 55 gallon drums of it that they bought, lol.
Dibbons, This week I re installed that panel in my 65. Surprisingly it was still a medium glossy black.
Assuming you’ll be installing carpet, I’ll offer an unsolicited amateur pro tip: After that floor panel is installed, install the piano hinge first, then the trunk divider.
Trying to install the divider with the hinge attached hinge used up all of the curse words and put a crick in my back. Defeated, I had to retreat and regroup: hinge first, then trunk divider. Sorry for the rant, but yesterday was painful.