I have nothing to base this on other than "it makes sense", but it seems like there has to be some form of revenue sharing here. OpenTTD is the reason why atari can even think this rerelease would work. I'm not saying there wouldn't be interest, but that I don't think any of the suits at atari would think to do this without OpenTTD keeping the interest there.
If there was any kind of revenue sharing, I'm sure it would have been in the OpenTTD announcement, and not the pure lawyer-speak version they did release.
why do you think a revenue sharing is more likely than Atari simply pushing around the volunteer project (and the OpenTTD project simply not risking any kind of legal conflict)?