I downloaded unofficial patches 1.19f and 1.19h, but 1.19f is just the u9.exe that asks for the game cd if you run it. 1.19h actually looks like an actual patch, but It needs to be installed on top of 1.19f. I don't even know what version GOG is so I don't know if they already have the unofficial patches installed or not.

GOG's U9 comes with 1.19f.

You can check version at journal :)

Aenvar is basically correct, at least for the purpose at hand. But please note, that the versioning (1.19f) in the journal will NOT change after you successfully apploed the new patch. So no "1.19h" or whatsoever despite the otherwisd correctly installed inofficial patch