Barracks with reactor or techlab?

Any way I can tell if a barracks has a techlab or reactor attached? In the units list I only get Reactor and TechLab entries with 4 Barracks but entries like BarracksReactor are not on the list (yet they are part of blizzard's unit list). I have an idea to check the distance of a barracks to find a nearby reactor or techlab but I feel this is the wrong way to do it.