Regarding the size of the tiles they have the same dimensions, but regarding the thickness in my case not.
The tiles of my version of "carcassonne für 2" are much thinner than the tiles of the demo version.
Ps:
btw. the tiles of the travel edition are also slightly thicker as the tiles of the demo, but here the difference is barely visible.
Travel: slightly thicker than Demo
Demo: much thicker than Für 2 & slightly thinner than travel
Für 2: much thinner than Demo