Kakashi did have the Sharingan when he the fourth was alive. So he may have had an oppurtunity to copy it. He may not have been able to use it, but he may have copied it enough to be able to teach to Naruto. Kinda like Sasuke being able to see Lee's fast moves but not being able to copy them because he had to be faster and more developed in order to use them. So I think that it could be possible for Kakashi to know some techniques but not be able to use them due to limited chakra or not enough experience to use it.