I should have more carefully said Norma was the first company to commercialize it and produce a factory formed case rather than rely on converted 284 Win cases, and to produce commercially loaded cartridges. AFAIK, that is correct. When NECO began to import the Norma brass into the U.S., originally, I got 500 of them. They are a little low on case capacity in that run, as compared to current, but I've been satisfied with the performance I get from them (still have some), and don't feel a need to have any more powder to help burn the barrels out any faster.
That the cartridge was originally a wildcat that a number of folks made on their own, is a history shared with a good number of other cartridges that are now commercially available.
Tim's post is a good reminder that not all the rifles made for the wildcat versions are necessarily identically chambered. Wildcats usually go through phases before they become standardized commercial products, so you may see small differences in neck wall thicknesses or trim lengths that are intended for some of the early wildcat chambers. Perhaps even a little in headspace. Lots of folks order a reamer, but get a different freebore or throat length or neck diameter.
Once a wildcat becomes popular enough, before a major ammunition maker commercializes it they often go through a period where dies are made by the reloading equipment companies both for forming them from the parent case and for loading and reloading them, and these can vary a little depending whose set of drawings they were based on. Still, when you look at the SAAMI drawing for the .284 Winchester and the CIP drawing for the 6.5-284 Norma, the only difference, measuring from the head, is the Norma version is about 0.004" shorter at the shoulder intersect than the .284 Win. But all the case body diameters match, and I would expect that to have remained constant throughout the different versions. So it shouldn't matter much whose die you have as far as body diameters go, unless the die wasn't made correctly or unless your chamber is too wide.