Im wondering if that new Forum Adidas shoe w the Heitor model is a cupsole? Looks like a good shoe if you can rock the strap
it's pretty easy to distinguish. if the upper is put upon the sole representing a single unit, and then welded and possibly knit to it, its a cup. the cup being the sole unit, as the upper sits within that cup.
vulcanized means the sole and the upper are connected via the foxing tape on the side. the sole isn't a single unit, and the upper rests just on top of the bottom part, then foxing is applied to form a unit.
they also look very different aesthetically. there are simple cupsoles outthere that kinda look like vulcs, but soles like that forum model are always cup. you can't make vulc foxing tape look like that.
typical vulcs are most classic vans models, typical cup would be the heitor, a dunk, es accel. vulcs are usually thinner and more flexible out of the box, cups have more stability and allow the manufacturer to put extra dampening in there.
EDIT: what mostly works when your in doubt about it is that if you see stitching on the sole, it's surely a cup, even if that stitching is only decorative. i don't think you can put stitches through vulc foxing/sidewalls.
on another note, the heitor doesn't come with a strap i think, unlike regular forum lows.