I'm not sure I follow. It's possible to generate download keys for free games right now and hand them out. Are you referring to making it so when anyone downloads a free game they get a key?
Download keys right can have a "unlock price" set on them when you create them, which will let them unlock individually priced files. There's no way to generate a download key right now that uses our exclusive rewards system.
Are you trying to work with the exclusive content system or individually priced files?