They definitely look like convertible header moldings, you can even see the tell-tale weatherstrip rub marks on top. Not sure for what car though, most are not split in the center like that, usually it's one long center piece with caps on the ends.
The 60s-early 70s cars had that style with a joint in the middle, and the top piece covers the end pillar pieces. But the shapes are different from pics I've found so far. Very similar design to the Ford parts, perhaps look at 60s Tbirds? The shape is slightly different than Mustangs, etc. GM and Mopar usually had screw holes in the main top part, Fords did not. but they do look off topic for the main forum... here's a smaller image with both top and bottom
I actually had no clue what it was, just bored at work. Your post about 60's to 70's cars, but not GM of Mopar cars (holes) just got me to search late 60's Fords. The second thing I clicked on was the site Squablow referenced. They must be pretty scarce, because couldn't find one other listing, new or used.