If you trust your breeder, you can ask why they chose the dog. It should be fine. I am not sure whether you say you don't know the breeders because you got her from a middle-man or because you don't know her personally but bought a puppy from her.
If you bought your dog from the breeder, you can certainly call them and ask about the dogs in the pedigree. I mean, this is after the fact, since you already have the puppy, but there is nothing wrong with finding out about the dogs behind your dog, and a good breeder will try to help you out.
If you bought your puppy from a second party things are a little trickier. You are then dealing with someone who prefers to be so behind the scenes that she never speaks to or meets the puppy buyers. That person might not be very open to questions and suspicious. There is a possibility though that your pup was the stud-fee puppy. And the breeder who provided the stud chose to sell the pick puppy.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC