Rochester is a licensed distributor for Maxim and a lot of other manufacturers, and Digikey now has this 'marketplace' thing that they appear to sell through. So I don't see any reason to assume these are clones, and in fact when I look at the ones you link to they show the manufacturer as Maxim and that they're sold by Rochester. Even if they were clones made by Rochester, they appear to do a fair bit of licensed manufacture of EOL parts, so if they're clones they ought to be on the up-and-up, since otherwise Maxim wouldn't let them distribute.