Basically, feed store employees are often clueless. Any info you get from there should always get a second opinion from someone who doesn't work there.
They are well meaning but have much misinformation. Heard one recommend white leghorns as meat chickens! And another said to put 12 week old chicks on layer feed!
Usually if you talk to the owners, they are a little more informed.
From looking at pics on google, I would say you are correct and those are probably not Pekin. Though they may come in other colors... I'm not buying it.
Sometimes hatcheries substitute orders. Orders can get mixed up as well.
They are obviously unfamiliar or they would have known upon delivery that they weren't Pekins which should have the yellow plumage and bright orange bills and feet, Though some looked pinkish as ducklings.
Every hatchery I looked at just now had ONLY white pekins. And none of them looked like your adorable cuties.