--sorry for screwed up formatting on this post. Can't seem to fix it, and don't have time to start over...
Gibson did move the neck joint to the 19th fret (like a 335) in 1968, and these are called "long-neck es330s or 330L's."
There are a couple, both original and reissue, on sale on Reverb:
We had a thread. about this years ago. There's a post that I think TalismanRich made that shows the interior of a 530, which has a pretty substantial block.https://www.heritageownersclub.com/forums/topic/37263-question-about-the-h-530/