Since I both sold and owned a couple of these puppies when they were brand new I thought I'd offer some data you might find useful about this kit...
First thing: the car on the cover and the car in the box are different models. The car on the cover is an F-85 Holiday Coupe, model 3617. The kit car in the box is a Cutlass Holiday Coupe, model 3817. Both equipped with either 4-4-2 performance option L69 which came with 3-2bbl carburetors or option L78 which included the more common Quadrajet 4bbl carburetor. Both of these packages included the red line tires shown on the box along with heavy duty wheels. A no cost white wall exchange option was also available.
Getting back to the box art, it was definitely Photoshopped. The tell-tail clue is the two-tone/vinyl top chrome separator between the windshield and the side windows that they forgot to remove when they were making the changes. From my experience, average buyers bought 4-4-2's with a vinyl top. Boy racers skipped the vinyl top but equipped theirs with heavy duty items for weekend fun at the strip. some of them ran at U.S. 30 Dragway in Indiana where I raced GT 350H Mustangs courtesy of Hertz.
Just in case you're interested, the following interior colors were appropriate for both the coupe and convertible versions of this kit.
Parchment Pearl (Opalescent) white with matching headliner and black carpet, black with Ivory headliner and black carpet, red with Parchment Pearl headliner and dark maroon carpeting and blue (matches 66 Olds color code D Lucerne Mist) with matching headliner and dark blue carpeting.
Vinyl tops came in Black and Beige (actually an off white)
Convertible tops came in beige (Khaki comes real close), black, blue (a bit darker then the interior blue and white.
I'll be posting the actual paint chips and swatches of everything at the Resin Realm after the first of the year. The pic is of two of the pages from the Olds Dealer binder.
Hope this has been helpful to you.