No, the dumbing down of Web to only describe floor surfaces is entirely a Larian rendition. Have a read through the spell focus thread in the stickies, Llev; I briefly discuss Web and the game's implementation of it compared to how it's written in the 5e books and how it should work.
Also, it looks like female Gith can also eschew their spinal columns at will, or at least that they're far more hyper flexible than human ones. Quite fascinating...