Here is what I think I know, so far: The first gen 3 hole (Gen IIA) wheels where the two smaller holes are smaller in diameter than Gen IIB may have been supplied up through 5S118 based on photographs. There may be some Gen IIA wheels with inconsistent hole spacing because they were hand drilled. All of the 3 hole wheels that I have seen were supplied with chrome plated hubs (AKA Boss) with at least one exception where it looks like there was one or some wheels supplied with aluminum hubs fitted with the original Gen I bolt pattern. The original early bolt pattern from the 16" Cobra wheels was uniform spacing (from what I think I know) whereas the wheels supplied with the chrome plated hubs had wider spacing at the top of the wheel bolt pattern. I am looking for hard evidence and more detail.
The holes on the Gen IIA wheels measured in diameter approximately as follows: 0.89", 0.63", 0.48". (Thank you Scott Evans)
The Gen IIB wheels measured approximately as follows: .835", .665", .615" (Measured myself and confirmed on the original drawings). (Thank you Rich Williams for the loan of the original wheel)
Here are photos of each example and one of original manufacturer (FYI, I will be at Sonoma and would be happy to discuss this topic and receive more enlightenment. With luck, I will have the new wheel made on the original tooling with me.) Photos courtesy of Dave McDonald and now defunct World of Speed.
I expect these new wheels to be available for purchase within the next few weeks direct from the manufacturer. More to follow.