Here's the link to a pic of the '68's interior panel. Although the photo does not display it all that well, it is most certainly pearl.
/forums/ubbthreads.php/topics/85963/1.html

The '69 interior does have pearl visible in the headrests, where the upholstery is not too sunbeaten. And they are bent bar headrests, so they are most certainly '69 pieces.

The pearl effect seems to be a surface layer lamination, the seat panels on the front seats, which are quite worn, did not display any pearl appearance. But on the rear seat side panels, behind the armrests, and the sides of the rear seat displayed a brilliant pearl finish. Dark Turquoise in '68 is also a pearl upholstery.