And to be honest it doesn't take much of an eye to tell the difference between the common ones that Petsmart carries. Avoid the pretty blue vertically striped ones (juvie M. lomabardoi aka kenyi), the horizontally yellow and white striped one (M. auratus) and the vertically striped yellow and black one (Ps. crabro aka bumblebee). You can get the red one (red zebra), the all yellow with black in the fins (L. caerulus aka yellow lab), the all blue one with black in the fins (Ps. socofoli) and MAYBE the blue horizontally striped one (possibly M. cyaneorhabdos aka maingano, electric blue johanni), but these can be hybrids (between closely related fish).
Those are pretty much all the common cichlids you'll see in an "assorted" mix. If you aren't breeding for sale and just keeping them for your pleasure, these are fine. You can't be positive they aren't hybrids (not from PetSmart). If you see anything that doesn't fit this description, take a picture and post it in the African ID section before you buy it.
I do recommend though that you have at least a 55 gallon tank (though your big guy would appreciate at least a 75 gallon since a 55 is only 12 inches wide and the 75 gallon is 18 inches wide, more turning room at full growth). Oh you'll also sometimes find you Nimbochromis in the "assort" tank though I have NO idea why they mix a hap that can get to 10 inches in with mbuna where most max out at 6 inches. People often buy them not realizing what they really are.
C. Afra "cobue", Labidochromis chisumulae, M. joanjohnsonae,
Ps. acei, Ps.cyaneorhabdos, I. spengerae
46 Bow front
Ps. saulosi, Labidochromis chisumulae