While the combination print could be a fake, there are 2 things that vouch for its authenticity. One is the desity of the rock in the right places for a footprint, and the other is the size of the track. Although making a track by drying mud is possible, fakers would try to make a more standard size foot.
The real take away from the track is that the tracks keep going under undisturbed banks. If there were scientists that were really interested in the truth, they would have investigated further. But they aren't really interested in the truth.
Yeah. I've seen images like that where a cross-section proves it was carved and others where the cross-section proves it wasn't.