How can i get 2.60.2 for the GOG Version?

You can't. Snowbird is one of those asshole devs only caring about steam. The game is only on gog for a quick cashgrab. Like Snowcastle (must have something to do with "snow" in the name) with Earthlock. But there are other devs doing the same. Is one of the main reasons many people stick with steam: gog = waiting for weeks or even months until an update is available which was pushed on steam first.