Yes, there should be 2 separate listings on the
Larian Vault D:OS kickstarter management page, which you can individually select between the Larian Vault, GOG or Steam.
If you mean install them on the same computer, then you should more than likely be able to. I have the Steam and Larian Vault version of Dragon Commander installed. They both store settings and saves in the users' My Documents folder, but if that were a problem I could set one up to automatically run as a different user.
