Is vertex shading allowed on model exports?

[Filler]

As some model formats, like FBX, can do vertex shading exports, I thing.

Mostly because I spent a couple hours doing this, as someone sent me a clean Conker model rip, something I struggled to rip myself right, vertex shaded it myself with heavy reference on the actual model. Not 100% accurate, but it looks pretty decent.



Or does this count as custom?