Hey Steve, Congrats on the very well equipped "SS" and the build sheet makes it all the better!!!
I grew up about 15 min from that dealer, 1st build sheet I ever seen from there.
I have a 72 that I am restoring and on my build it list the radio as a "UM2 AMFM RADIO/TAP" (no room in the column for the "E" on tape) so I would think you have the AM FM only. I am not sure but I think one of the numbered boxes on top shows the radio harness, someone else might know more on that.