They last hit the road in 1988 and had been resting on rims, leaves, and dusty cement floor in dry rot neglect.

As you can see the old tires were aged. Visible in the image are sidewall checks and splits. In other areas the tread has separated from the tire casing.

NOS tires  were sourced and shipped. The originals delivered with the car as new would have been the optional  weißwandbereifung [white-walls] that were in vogue in the USA market during that era. White-walls are exceedingly popular for collectors but I consider them an overly used gussification;  (ditto for continental tire kit installations, added rear fender skirts, and dangly things from the inside rearview mirror).

This Michelin “X” tube type radial is period correct and to my taste an authentic european sporting look.