Am I eligible for an Premier space available upgrade on a domestic coach reward ticket?

Before the merger I know that was not possible, but I currently have a reservation to the Caribbean that I booked using points. When I look at the reservation and drag over the segment flight information, it says, "Eligible for Complimentary Premier Upgrade

You are eligible for a space available complimentary upgrade to United Business on this flight, starting 48 hours before departure. When available, these upgrades are cleared automatically and in priority order."

This seems to contradict with the following "Complimentary Premier Upgrades are available on all paid, published fares." that is found here.