This is slowly being recognised as an increasingly important concept. For example, in quantum mechanics, one witnesses a consistent, but often unconscious attempt to arrive at first class theories. It all depends on context. In computer science, the principle of first classness is expressed in the Object Oriented paradigm that every entity must be an object. In this case the property becomes synonymous with type or class of object.
Every object is an instance of a type.
In order to obtain first classness, the types must themselves be instances of types. In other words, Analytic Philosophy is based on a methodology which restricts it to considering and admitting only second class theories. In this perspective, type becomes synonymous with the property possessed by the instantiated objects. If every type is itself, an instance of a type then it can also be considered as an object. What is an object or a property depends on context in some way.