vin code is RS23L71189757. Not sure if that makes it early or not.
Sorry for the delay; it's been a crazy few days here. I checked my car, and it looks exactly like yours does. I have three holes in the RH inner fender apron just like yours. Screws have never been installed in them, and mine is an original paint car, so I'm confident that these have never been used. Apparently these holes are just left over from '66, and not used on the '67's. Hope this helps.
Cheers,
JD