Slitherine

I recently bought Panzer Corps 2 base game from Gog and now I want to buy the campaign DLCs. Can I purchase the DLCs from Slitherine and use them with my Gog base game? I do not use Gog galaxy and only use the standalone download installer from Gog for the base game.

I'm sorry if this has been answered before, but I looked and really couldn't find the answer.

Thanks,
Purrfang

PS My friends call me Purr and my enemies call me Fang...