The best way to replicate as best and accurate as one can these vintage cars is to use vintage material showing the car at their time of use, restorations and "tribute cars" usually can not be used as a guideline for details because alterations or modifications. I never ever say my models are "exact" replicas of the actual cars they represent...some details and or specifications may be incorrect or not in "timeframe"...well that is ok with me to a point, but I do try my best to do as close as possible to the car real details and specifications, because I enjoy the challenge.
The posted 1978 Glidden Fairmont in my opinion is not the real car, just look at the rear fender wheel opening and molded/stamped arch flare, the Glidden car did not have this and is clearly seen in pictures of the car...including the two posted by a gentleman showing the car fresh from paint and assembly and still not a single decal/sponsor added to the body yet...so from the beginning the car did not had this, you can also clearly see it in the magazine article.
I very good friend of mine, who had quite a knowledge of these eras pro stock cars, told me that the real undefeated Fairmont was destroyed in a transport accident, but never fully confirmed...others say it was sold and converted to a "private pro stock car"..then stored for years ( seems it was painted in yellow and other colors)...then "rediscover" and "restored"...but I don't know what in the end is real or not.
So your best bet is only to use visual info from the era, A LOT of photos of this car have come forward from people who took the photos in 1978 with personal cameras, some where even Bob G. friends and employees.