Deozaan: Keep in mind that installing the 2.0 beta client will uninstall the 1.x client. So you'll end up with a beta client you can't login to and no way to use the 1.x client.
freezing_rain: That's not true. I have two GOG installations now. The usual old GOG launcher in its default "GalaxyClient" folder and the new GOG 2.0 in the new default "GOG Galaxy" folder. Two seperate installations. I can still start the old launcher (or the new).
When I installed the 2.0 client it didn't give me the chance to customize the installation directory and any attempt to open the old launcher just opened the 2.0 client.
I suppose it's possible the 2.0 client updated path in the shortcut in my Start menu. I never checked the actual installation directory to see if it was still there.
Thanks for correcting my mistake.