[Lynn]

I have seen both in my limited experience. Take the following only for what it is worth. I have nothing definitive.

The original spare on my 69 Z/28 was had a 627, and I believe it to be original, but no way to prove it. My brother bought the car in 1975. Don't know why it would have been swapped.

OTOH, the original spare on my 70 LT-1 Corvette had the first type you posted. It is not in perfect shape; has been scraped somewhere along the way. PIC below.
Again, I believe it is original, but also no way to prove it.

Several survivor cars on this site. I forgot to look at the ralley Green survivor Z at MCACN to see what it had.

What does Steve S say? He would know. Tim would be another great source, given the survivors he has. I did not look to see what Tim's survivor Corvette (achieved Legend status) had for valve caps. I don't plan to have either of my cars judged, so don't really care that much.