I think that makes sense for Tundra/Sequoia vs Taco - but I kinda doubt that it is different for any of the midsize group (LC300,250,GX,Taco). Someone will have to get some specs when they come out. The reason I think at least the LC300 and GX are the same is that the two are offered with the same engine, wheel base, and the same tow capacity. The wheel base, GVWR, and hitch tongue weight are the primary factors that would drive engineering choices for frame structure. No published curb weight or GVWR yet. Once those are out we'll have a really good idea of how similar or different they are. And it may not even be the same chassis between the engine options. Lots of unknowns. But, I'd bet that the GX ad LC300 are very similar if not sharing the same side frame rails.
Yeah - they're all assumptions. My point was more that it's definitely a process they've considered/implemented, rather than conjecture. Everything else is still up in the air other than what we've seen.