As i understand it most dwarfs are hybrids, the 'pure lines' are closely gaurded, yuo will not find them in shops at all. I was confused by this too as my dwarfie looks so much like a winterwhite Ii was convinced he was one, but now I have read up and understand more I know that he cant be a 'pure'. Some dwarfs with have more ww genes and some will have more russian genes, that determins what they look most like.
Not sure about syrians as I dont have one myself, and when I guess on colourings I usually get in wrong. Nooboo and Souffle are very good at this kinda thing.