Hmm, so I just gave this a quick thought. If I understand you, then the idea that epistemologically speaking, knowledge about reality cannot be known a priori (at all) is hardcore empiricism.
The idea that no concept we ever "stumbled upon" is a product of some Platonic a priori recollection is, again, some form of empiricism.
You're using metaphysical terms though, unfortunately I can only think of epistemological positions.
However, if I take your question to be more nuanced, then perhaps we are talking about scientific realism versus scientific anti-realism (instrumentalism, conventionalism), or a milder realist form called experimental realism (see Hacking). But as far as I'm concerned, I don't know the implication of empirical proofs on the a priori status of the "concept of reality". These positions are more like assigning existential quantifiers at different scopes on different sets, rather than on their epistemological status.
Perhaps you can elaborate?