I am really confused

about this coat thing. I thought all yorkies were the same but from reading on here some can be soft and some silky. I have posted on here that I am allergic to our pup 11 weeks old. He has a very fluffy soft coat . I thought he would lose that coat and get a silky coat but I have found out that some are soft coat yorkies? and not silky. His coat is very dark black with a lot of black around his face and legs as well.
I have no allergic reaction to my two year old yorkie. Got him at over a year old and he was always silky.Different breeders .
I have read that yorkies come from silky terriers long ago so just thought the coat was always silky unless they were mixed breed.
If anyone can clear this up for me I would appreciate it.