I believe your observatins are correct. There are other things that look wrong too. For example, chrome tail pipes. Also, according to Jerry's book, VIN 508... were built in November, not October. So, he has some facts wrong too. I am always suspicious of such vehicles when there is no picture of the trim tag or partial VIN on the block.
I note lots of bids, but the price is too low for a true numbers matching RS Z IMHO.