jetav8r,
I bought my Hasegawa AU-1 from Squadron about a year ago. The Hasegawa kit # is 09395:2400. And, you're correct in assuming that the F4U-6 and the AU-1 are the same. The Marines were originally going to call the new version the F4U-6, but, after considering how the plane was going to be used (primarily as a ground attack and utility aircraft), the decision was made to redesignate it to AU-1. It was the last variant of the Corsiar to be used by the US military, as the F4U-7 (the last Corsair variant produced) was sold exclusively to the French Navy. I hope you have good luck in finding the kit. If you can't, just e-mail me, and I'll get one to you, as there are many of them on the shelves at various locations here in Indianapolis, IN.