I don't know about those companies and have enough trouble with dating some zippers for that fact. I do know that your skirt looks original to the mid-century, the fabric and all. Honestly with many of the circle skirts that I get in my inventory, guess what is the most common thing that is missing??...the hook and eye. Even if you do put in all of this time finding out its origin and dating, it may not offer you any pertinant information about this skirt. Personally I would let it go, BUT if you like a good mystery and enjoy sleuthing, then by all means continue. The information you learn about these button and hook manufacturers may be beneficial to us all :spin: