Hmmm, I'm running 27.1.1, and under Color Books, there are no Pantone Solid Coated or Pantone Solid Uncoated in the list anymore. They are there with a "+ CMYK" next to them, whatever that means. However, I read of a workaround somewhere that if you have an older copy of Illustrator you can copy the Pantone Library from there and add it to your existing libraries. It worked for me anyway.
Steve