I just spotted your very old post (forum suggested it
), you probably found out by now that it's not a neck-through construction. Anyway:
Peter Mac referred to the "center block", which was initially massive
in that the only wood removed was the pickup routes and the mortise for the tenon. This started changing after the introduction of the 355/345 and particularly the varitone switch option in 1959, access cutouts were added particularly to the bridge PU routes. This is unrelated to the block marker version though, the change was gradual, inconsistent and took several years - apparently there are mid-60s block marker 335s with no cutouts and early 60s dots that have them.
In the Norlin era this was done to an extent that there was barely wood left for a proper center block and the tenon wasn't visible in the neck PU cavity anymore. The center block did not really connect the neck with the bridge posts anymore, but that wasn't meant to be its purpose anyway, which is why the term "sustain block" is wrong: The idea was to "deaden" the top to get the most feedback resilience out of the construction, that's also why Gibson started happily adding ply after ply to the initially 3-ply tops around 1960.
SA2200 vs Norlin era 335 bridge PU cavities: There is no center block anymore, you stare directly at the bottom spruce bracing.
This is also why I wrote "The mid-Norlin-era 335s should be called "332.5", because there is so much wood missing under the top [...]
" in my (shameless plug) SA2200 review
- they're halfway 330s and considering how much the electronics varied on top of the construction over the years I find it funny when I see people referring to "the 335 sound", which is then described in occasionally very contradicting ways.
Norlin era neck PU cavity - were did the tenon go?
Modern era 335 (Memphis)
That ambitioned replicas like the Tokais or derivatives like the Ibanez AS or Yamaha SA were sticking to the original specifications years before Gibson (kind of) returned to them isn't surprising of course. BTW, Tokai is doing its own way of an access cutout as shown on this ES-150:
Basically a "best of both worlds" solution - easier access for everyone but still plenty of wood left for the toan