St Louis original-fender-tag car should have evidence of its left corner bent for painting, IIRC.
If the seller has no pre-restoration photos of the GTX side trim, then without a forensic inspection, I'm thinking re-body.
Just seems odd to me that someone would add the bottom rocker moldings.
Note contour of the lower area of the rt door, and gap between grille and hood.
Interesting touch is the beefed-up front seat bolsters.