Base interior was Reed grain seat inserts, unpleated for most if not all of '68 run.
Seat inserts changed to the VW-Beetle-like pattern for '69 (and maybe some late '68s, as the flat Reed inserts were prone to stretching out and may have become a warranty annoyance)
The trim panel photos show both grains, the Reed being the "basketweave" type.
I'm not sure that the base trim panels actually changed from Reed to match the seats for '69, as I recall a couple of original base '69s that had Reed trim but the later seat inserts. Chrysler was cheap!
Rear armrests were optional for base coupe interiors for '68, & I think also '69; check the dealer order / option info on the Hamtramck Historical site.
Aftermarket trim cars have had slightly thicker padding than OEM for a long time, difference in appearance aggravated by the aging of the OEM panels.
Generally speaking, Legendary is more accurate than PUI.
Love base trim coupes, I've owned 3.