That's the weirdness of it all: nothing changed about the trunk shapes of Darts and Valiants (respectively) from '65 to '66. Maybe a slightly cheaper mat for the Valiant as a cost-reduction measure...? AFAIR, all the repro trunk mats presently available in North America are one part number for '63-'66 Dart and Valiant. Without looking, I seem to remember some vendors offering Convertible-specific mats. Large physical interchange on these; the '63-'66 A-body repro mat fit nicely in my '62 Lancer (which now has an ultra-deluxe mat sourced from Australia).