I've noticed the Stone Zealot Base doodad will act like a bridge (raise unit's height) but the Temple Stone Inlay doodad does not.
Tried looking at the Actor and Model differences to determine what flags are different.
Is this data part of the m3 file itself?

Tutorial?

It's part of the m3 model file, yes.

There's also a model flag in the editor called "Dynamic Z Changer" which is needed if your bridge can "lift" like an elevator.

So sad.

I wish the Cut Scene editor would let you save a Cut Scene as a model to be used in game, that way one could utilize an existing platform-enabled model and turn it's opacity to zero.