Never thought about this and I'm sure the answer is yes, but it's always worth checking. Can I switch standard '68 seat belt buckles over to deluxe without having to buy new belts? Meaning, will the clips fit and hold if I just switch the buckles?

I would say no.....the standard and deluxe buckles are different. Do you have a buckle to try and see if it would work? That would be the only way to know for sure.

The deluxe buckles and tongues are different than standard buckles and tongues. They are a matched pair.

I would not trust the belt safety trying to mix the two types.