I did quite a bit of research on these little jewels before I picked one up. That was around a year ago. Like others here, I also questioned whether these amps were truly made in the US. There was even a folder in my browsers' bookmarks where I kept all the references. Thinking I wouldn't need that info any longer once I acquired my GA-5, I chucked them all. Now, I'm wishing I'd have kept those bookmarks.
I do remember that I decided they were certainly American made. I'm going on memory now (a dangerous thing...), but as I recall there was some connection with Mojo - maybe even to the point that Mojo was making them for Gibson.
Perhaps we just need to ask Gibson?

I imagine they would be none too happy to find folks were claiming their little amp is of Chinese origin when they've taken such pains to point out that it isn't.
I don't mind asking them ...they don't bite.
~