I'm with Shawn and others, I think it's original paint. You can still see all the file marks around the joints that are typically filled in during a repaint. One of the pinstripe closeup shots shows the edge of the masking for the darts, and it looks natural, not hand taped. Might have been dismantled for a super cleaning at one point though, but maybe not? As for the paint flaking off the bottom bracket and looking like dried desert mud, I've seen this a few times before. Not too unusual.