If you think about it the small vertical panel would be painted in body colour during the main paint process, they wouldn't bother masking that off. But I also doubt they would have prepared the area properly for paint, so although coloured it probably looked lousy so it wouldn't surprise me if they'd gone over it with matt or satin black.
I looked back over my photos and this is one I took on the way home after buying the car, which at that time hadn't had any paintwork done. A one owner car, the PO added the pinstripes but never had to touch the paint, in fact one of the selling points was that the bodywork was totally original, no accidents/repairs, not even gelcoat ones.
Which surprised me because I thought it was something I'd done, but obviously not.