I read the articles and the options lists for both the '68 and '69, and only F-70's are listed, not G-70's. If the G-70 was a mid-year change, then it should have been offered on the '69 but obviously it wasn't.

Also, the '69 got the 14x7 wheels but still had the F-70s. Seems very doubtful that Pontiac would put a wider tire on a narrower (14x6) rim in '68 but not use it on the new wider rim in '69. The AMA specs list the F-70 Polyglas for '69.

I think we're back to square one.