Seeing worms in a dog's poop is a GOOD thing - it means they're leaving the pup! Yes, you should deworm them again. I have to do that to my new pup, too, who had quite a few worms in his poop the first couple days after being dewormed before.
If you're concerned about them not acting "right" or seeming to be "off", though, a vet visit sure wouldn't hurt since they're so young and should never really be "off" at that age
