pablodusk: It should already be patched to 3.0. Full disclosure, I own the game from another store, but the game directory contains the README.txt file from the 3.0 patch, and I assume the GOG version is the same.
This is correct - gog.com is selling game version 3.0. I have the gog.com version and the following text is in the README.TXT file:
*** COLONIZATION Ver 3.0 Readme.Txt ***
================================================================
This version contains fixes to problems in Colonization that many people
have found that should take care of the "random" lock-ups and make the
game run a bit more smoothly. It also includes several extra features
we hope will add to your enjoyment of the game.
Fixes for Version 3.0
1. The "U"nload key working during a boycott.
2. The Cathedral now requires a population of 8 (as
stated in the manual) instead of 16.
...