The 430/530 GPS is PRNAV approvable.
The installation is not however. There is a process for doing that, which the status of the GPS itself merely makes possible.
I don't know any more detail. I think there are some documents on
PPL/IR about it. This PRNAV thing has been going back and forth for years now and I have stopped following it.
The number of GA planes that are PRNAV approved can be counted on your fingers. The pilot also needs some kind of approval.
It's all a load of Euro bollox.