O yeah, it is definitely possible to find pure breeds there but not very often. Personally I'm not too familiar with African to be able to point out the pure strains from the mix breeds. Lol I even have a hard time telling some pure strains apart from one another sometimes.There is no doubt that the "assorted" cichlid tanks found at LFS's often contain hybrids. That being said, I've scored many pure bred cichlid trophies from such tanks and saved a bundle.
One has to be careful & be somewhat familiar with desired species before buying.