In my experience all bike racks are universal, in that meaning by hook or by crook they will fit somehow, but they might require a bit of fettling with nuts, bolts and bits of metal.
I have a Bor Yueh rack I scrounged out of free cycle, it fits and is very solid, the weight it is designed for I have no idea, but when the rack is loaded for my commute, I cant even lift the back end of the bike, the panniers are that heavy, but am always carrying books, laptop and tools.