Don, I'm pretty excited to see that first pic. Two things really jump out at me:
1) The tail surfaces are built-up, not sheet. The only plan I've ever seen with built-up tail surfaces was the Model Airplane News plan, part of Jim Van Loo's original construction article in the March 1968 issue. If this picture was taken in June of 1967, it could't have been built from the MAN plans. Below is a picture of Van Loo's '67 NATS entry (Chris McMillan photo) - you will notice differences with your picture - it's not that airplane.
2) Also in your pic #1, notice the shortened elevator counter balances.
3) Also the canopy appears to me to be a standard "bubble" type canopy, not the same as the canopy on Van Loo's '67 Chipmunk in the McMillan pic.
So was this airplane a Chipmunk design by someone other than Van Loo? Or is it Van Loo's very first one, that he took along to the NATS as a backup? It's a mystery.