I was under the impression that you had a female and a male for sure. I was positive that the male was on top in the first pic as there was absolutely no pink on the belly (I couldn't really see the bottom fish all that well). From the pics posted since then it is clear that the fish on the bottom in the first pic is indeed a male, but you also have a male in the top as well.
I have 4 spawning pairs of GBR's and as hsherman1986 said, females will always have pink bellies. There colors may become more intense during spawning periods (actually, my alpha male's pectoral fins and part of his underside become black) but you should always be able to see some pink in a female.
They are no doubt GBR's and not one GBR and one Bolivian for the reason that WaterPond pointed out: Bolivians do not have red eyes, they also do not have blue spotting, they are usually quite a bit larger, and the fins are differently shaped than GBR's among other things.
WaterPond: GBR's are usually "mature" at about 3-4 months of age but they still continue to grow and color. I believe that the term is used more to describe the ability to reproduce rather than as a sizing/growth guideline.