Thought I'd follow up with some plastic cap details. In order of the 3 caps pictured below:
The 69 Camaro cap is 2 3/4" overall length, is vented, and only one line of script on the cap: "Fill to Proper Level Use Approved Fluid".
The longer version is 3 3/4" overall, otherwise it's the same. I thought it was for full-size, but that's not what the parts manual indicates. Maybe it's for different division.
There's a later cap that looks similar, it's 3 1/4" long, but the fill marks are in the same locations as the 69 Camaro cap. It isn't vented and has "Do Not Overfill" added to the cap. The attachment of the dipstick is slightly different.
