It could be.
I know when I brought my cat Doodles home from the shelter, the other cats she was with were sick. She indeed later on in the week started showing symptoms of upper respiritory (sp?) and was sneezing, runny eyes, etc. The vet said she was getting over it when we brought her in, but sure enough, we had to bring her back because she wasn't getting over it like he had said she was. He had to listen to her lungs, and they were congested.
I'd have the owner take the kitten to the vet. Better safe than sorry!