I suggest adding:

Q: I've patched Fallout to the unofficial TeamX Version 1.3.x . It still says "Version 1.2" in the main menu, though. Did I do something wrong?

A: Not necessarily. The patch did not include a change of version number in places such as the main menu.

I installed the OSX version of this game, question is: are any of the patches compatible with this version?

What exectutable does the OSX version use? If it uses windows executable, then probably. Otherwise probably not as at least TeamX's 1.2.1 Universal patch, 1.3.5 unofficial patch and their mods use the windows executable as does high resolution patch. The Childrens patch does contain DOS exectuable so it might work.