I cant see how that is a Nickey Camaro. The Revell model has a better claim to Nickey heritage than the car for sale does. And obviously, cutting a ads out of magazines and adding door stickers do not provide provenance.
That car reminds me of so many 'built' cars back in the day. 12 bolts, big blocks, 302's, and associated speed parts were easily available and relatively inexpensive. Owners that wanted to, could buy the performance parts and upgrade their ride. The velvet interior suggests this car was revamped in the early 80's. The RS option looks original, but there's been so many changes to this car, and they look to have been so long ago, that it's tough to tell.
The body and undercarriage looks fairly straight and clean. The seller should have provided more pictures of the undercarriage and less pictures of old advertisements.
Without any real proof to the contrary, I would assume that car started as a plain jane, had everything added onto it, and price it accordingly.