The only option listed on the bill of sale for my 1973 240z is a "padded console armrest". I am the second owner and a personal friend of the original buyer. The car was well documented and all receipts saved in the file I now have in my possession. I have to assume this is the original armrest as my friends state that it had never been replaced, nor is there a receipt for any interior work. Any thoughts from anyone on the subject...?

This is pretty much identical to the dealer-added armrest in my car - mine does not have the raised bar on the underside.  Mine was surely the AMCO offering pictured in the ad, as the dealer had already installed the front and rear overrider bars and lots of other add-ons.