No. I'm not addressing Katello functionality on F18 at all. Just packaging. On Fedora 18 is Rails 3.2 so we in fact could not run on anything older then rails 3.2 on Fedora 18.
My goal is to create package and then install it and and run tests. Of course I'm trying to not affect F17/16,EL6. For that is there that if-condition.