Hard to tell, as photos/lighting often present only so well. Usually red sex links, aka Red Stars, are slightly more chipmunk or a bit variant in coloration as chicks, but still, they could be red sex links. You'll have to see if a lot of white feathers come into the mix in a few weeks. Here' a picture of some of our RSL chicks. Fairly similar.
Most hatcheries sell a sort of generic red bird and call them anything from New Hampshires to RIR to production reds. Here's a BYC member photo of true RIR chicks. Your's are a bit too light and golden in color to be RIR. RIR chicks should be deep red colored, even at hatch.
But feed store chicks could be most any kind of red laying strain. You could call the feed store and see if they know/remember what it is they think was being sold. The important thing is to enjoy them, keep them healthy and growing. Best regards.