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NOW it works.
I had greyed out install from main page in galaxy using bookmark, removed bookmark and found it in Owned games with the option to install.

Might help if that was the problem or i just did it the exact moment install got possible.
Just completed installation and started it. Looks really pretty.
Confirming, restart GoG Galaxy if you need. Worked to update the install option.
I didn't need to restart gog. I just switched bookmarked games and i was able to see it available for install. Its at 1:32pm when i seen the install available.