He was always pretty open about the fact that the parts were built overseas, but assembled and finished in the USA, arguing that it was the best way to keep costs down and quality up, and as most of us in this thread can attest he succeeded well on that point.
I have a 5 string MM, and recently picked up a JJ off ebay, and they're just some of the best feeling basses I've ever played. It's subjective of course, but I love 'em. I really want to catch a red-pickguard JJ (4 or 5 string) one of these days, I REALLY wish I'd bought one back when they were readily available.