I'm looking for a definitive answer as to the correct heater control lens on a '68 Firebird w/o AC. The sales literature on this site shows a lens which include the words "Temperature" and "Defroster", like the one I'm trying to replace. It also has the lettering below the control lever slots. The OER reproduction for 1968 omits this wording and also has the lettering level with the control slots, and has a dot above the word Air. The OER lens for 1967 appears to be like the one I have. However, the OER complete heater control assembly for both '67 and '68 show a lens with the words Temperature and Defroster, unless they are just using the same picture for both years in their advertising. Have tried to contact OER for an explanation but little luck with that. Am unsure where the lens that drop the words Temperature and Defroster originated, unless it was a mid year change. Would appreciate any feedback as to which is correct for '68.....Thanks.