An update:

Well, I took DS in for his K assessment this morning. He successfully identified colors, letters, shapes and numbers and was able to spell his name and repeat sentences back to the teacher. She told him to count as high as he could. He got to 110 and she told him to stop! She did not get anywhere close to his actual abilities in math or reading.

She asked if I had any questions so I asked her when he would be assessed for reading level. She said that she didn't really have time to do a reading assessment but maybe he could be assessed after the first month. She said they have a few kids who are "beginning readers". DS has been reading since he was 2 1/2. He is probably reading at a 1st/2nd grade level right now.

I asked about math. She said that she will try to group the kids who can count and do simple addition together. Also, she said she adds to the math curriculum (which is mostly about shapes) by doing patterning and "same vs. different". At home he is learning two-digit addition with carrying. I'm starting to get worried about DS...