Nice pickup, nice price, and judging by your description they are a m/f pair. Also judging by the pics they seem well bonded. Fairly sure they are Cichlasoma portalegrense aka the port acara. Aequidens and their relatives often cannot be sexed accurately by fin structure, the only sure way is looking at their tubes or venting. Almost certain if you take a gander at the larger ones tube it will be shaped like an arrowhead & angle sharply backwards toward it's tail. The smaller fish should have a much thicker/longer tube, and point straight down, the end of her tube will look very like the trigger on a gun & very blunt in comparison to the male's.
Correction, they do indeed look like A. patricki.
