The litter can be pedigree but not KC registered. If you want them KC registered then insist on them giving you the information. There are plenty of litters out there that are KC registered and the owners have done all the relevant health tests. A reputable breeder would/should provide KC names if they are registered and from there you would be able to look them up on the Kennel Club site and see if they have had the necessary health tests.
Good luck with your search.
On looking at your other query, it seems that you have already looked up the mother’s previous breeding history on the Kennel Club site, so are you now asking for the sire’s Kennel Club registered name or is it a completely different litter you are enquiring about?
From my own experience I have found that some breeders mislead (lie) about their puppies
. Take your time as the new addition will hopefully be with you a very long time.