I have two 69 vettes, one coupe and one convertible, to my knowledge both have original seats.

The convertible have seats without headrests similar to the right seat on the picture from Ecklers catalog, the seatback is 28" high. The coupe have headrests, and look more like the left one, the seatback is 23,5" high. In both Ecklers and Corvette Americas catalog there is only one part#, differs only with color. Covers for the headrest is sold separate.

I've tried to mail both companies, neither of them have replied.