The best way to find out would be to ask the person working there. They would know for sure...and if they don't..It is probably not a good idea to buy from them if they don't know what kind of fish they have because if they don't know what kind of fish they have then they are probably not caring for them properly. They are most likely peppered cories though. Cute little fish! I have 4 and I love them.
They prefer sand substrate. It is really cute to watch them dig their faces into the sand. Mine love sinking shrimp pellets.