As Ralackk said, GOG versions are patched to latest retail patch available barring compatibility issues. Some games have GOG's or unofficial fixes/patches applied as well when needed. And you can't generally use retail patches on GOG versions anyway as the retail patches restore any DRM and/or disk checks retail version of the game had rendering game inoperative.
Earth 2150 is a special case.
Online, the game is only played with either the community patch or the OPX mod. (And you are incompatible if you got another version)
But, at the same time, the patch breaks the balance for the campaign.
So it would be really useful to know which version the game uses.