FYI, there were actually two versions of white deluxe interior in 1968, code 730 (parchment-white) and code 711 (ivory-pearl parchment). Why GM did this is beyond me. 730 coded cars have black headliners with white plastic-vinyl trim (looks terrible) and code 711 cars have black headliners with black plastic trim (much bettter look). GM did not keep track of the different versions of interiors sold. Although all of the cars shipped to Canada are in the GM of Canada records. If you had access to all of these records, you would only know how many white interior cars were shipped to Canada.
Jerry