Hi Sophie
Your pups are a little too young to be able to tell whether they are black, white & tan or blue roan & tan. Most light blue roans look black & white for at least a couple of weeks, often much longer. One good indication is to look at the pads of their feet - if they are black or mostly black with just tiny patches of pink left, then your pups are blue roan or blue roan & tan (the tan markings are often not clearly visible for quite some time) Could the tan muzzles you mention actually be staining from where the pups are nuzzling against the milk bar - light pups often get a pinky/brown stain in this area while they are feeding from Mum. It could be that all your pups are blue roan & tan (though that would be unusual as only one parent is this colour). More likely that you have a mix of blue roans, blue roan & tans & possibly black, white & tans. If you want to contact me privately with their pedigree, I could probably tell you if there is any black & white in the pedigree, assuming the breeding is reasonably well-known lines.