They are the same species, just different subspecies. Some info indicates male N. BG will readily breed with either subspecies while male CNBG may only breed with other CNBG. The females don't seem to care.

I don't believe (pumpkinseeds)PS are even found in MS. RES are as are several other lesser known sunfish with nice coloration but PS don't come that far south as a native and I doubt anyone has stocked them.