For what it is worth, we could not tell if our DS8 was reading in K or not. We thought maybe he could when he seemed to know everything listed on his Pokemon cards, but were never sure if he was reading or if he had just memorized what they said from our reading them. He refused to read books out loud to us.
At the beginning of 1st grade we still were not sure of his reading skills. I was actually worried at that point, but then one day I asked/forced him to read a page of a Mr. Putter and Tabby book and he read it almost perfectly, with expression. He was tested for the gifted program at the end of first grade - he had the highest scores they have seen in a while. He was reading at least on a third grade level by the end of the year, probably higher.
Now in second grade, we still have to fight to get him to read. He would listen to books all day long if I read to him, but does not like to read by himself (except for Calvin and Hobbes.)