My experience is that ACC is the only company making these old carpets. I'm convinced that every company selling carpet for vintage cars gets their carpet from ACC. I've been through this a half-dozen times or more. Every carpet I've ordered through other companies comes in an ACC box.
I tried to order directly from ACC for my 65 Six Window, and their price was MORE than going through any other seller. I guess ACC just wants other companies to handle the end-user side of things. I got that six-window carpet from some other jobber at a better price than the quote from ACC.
NOTE! My guess is that ACC has huge rolls of the various carpets, and also has floor pan presses to press the various carpets into the right shape for your vehicle. BUT, there may be variations in quality control. The carpet I got for my 65 NYer was NOT any easy fit, and nor was the set I got for my 63 Riviera. My point is this: warm up the piece and test the fit before installing it, so you can send it back if you're not happy with the fit.