One/all of them might be a/the Harrison Deluxe Heater referred-to on the sheet - can you post links to photos of the heaters you are referring to?
The terms "Deluxe" "Air Flow" "Fresh Air" were sometimes used to describe the same heater in the same year. GM and its artists and "documenters" were inconsistent and "duplicitous". Heater names used in various A-D years have been listed/posted in the past.
Also, it is common that wrong year heaters were put in trucks (and non-Chevrolet truck Harrison heaters were put in trucks).
Post pictures and we can "get on the same page" and get helpful. Otherwise, meander on . . .
