We're trying to do it now. I think it may explain the origin of species, not just their persistence. Therefore it may be impossible to know if two isolated sympatric gene pools are permanently isolated- much as it is impossible to knwo when two allopatric populations have differentiated enough to be regarded as species. If female colour has no spatial element it is almost certainly polymorphism. It is likely that males will mate with anything that responds.
Females are choosy in polygynous species.
I think that females are pretty discriminating about male colour. In this case, the OB females are common and OB males extremely rare. The OB males may never get mated, and might be produced through as an effect of selection for female OB pattern. I note that your argument above assumes allopatric speciation- if males colours are spatially limited they may be something to do with species, if not then its just polymorphism. This shows you can't do theory-free science.