Greg, do you have data by serial number that would let us know if we own a pre punched horizontal or the earlier one? I ordered the earlier kit because I did not know.
I can only give you a maybe. That's some older info, and records from back in that period of time were on paper. I'd suggest you look at your rivet line and see if the rivets are equidistant from the edge of the material and between rivets as a start. In other words, does it look pre-punched? If the holes are not inline with each other, it's probably non-pre-punched. I can also see where there's a measurement we can provide. That might take me a day or two.