I had the opportunity to examine N500003 when D & R Stevie owned it. There is a very good chance that car was never in production at Norwood. Does not appear to have ever had a body tag; no con VIN on top of the cowl. Probably built up by Engineering from a production '68 body structure with some of the first '69 sheet metal off the presses. Had a hand-made dash cluster, hand-stamped 472 intake. Floor pan had the stamped hole with welded reinforcement, not the torch-cut hole seen on production 4-speeds. Bear in mind that it had some restoration work over the years. The 1992 Hemmings ad mentions 'YH 5 rims' which didn't exist until December '68. It was blue when I saw it; saw no trace of orange paint. But probably not painted as production cars were; may have been painted assembled.
It is not the first production anything because it was not a production car. The Motor Trend photo appears in the October '68 issue. Lead time in those days was about 3 months meaning it was a functioning car possibly by late June '68. Norwood produced '68s well into July. 1969 Camaro production commenced on or about August 22, 1968.
Larry Christensen has been around a long time. He may be one of the more knowledgeable guys out there and has done many fine restorations on some of the rarest '69s built. I found the first page of the article a self-aggrandizing attempt to position himself as "Mr. Camaro", apart from all those "arm chair Camaro experts" on the internet. I collaborate on '69s with a number of very knowledgeable people; none of us thinks we know it all. What we do know is there is always more to learn. Larry has chosen to not share his knowledge with the hobby and as a result is not well known. I can't recall the last time anyone mentioned him. Too bad as I'm sure we could have benefitted from his extensive knowledge.