I see no problem with it. Something I see as a good sign of a good breeder is if they don't breed individuals too often and give their moms breaks. Many good breeders already know or have a good idea of what future pairings will be.
Take your time looking for a breeder. Labs are really popular which means some people jump into it with no thought of genetic issues and temperament. In my opinion the popularity of a breed makes it tough to find a good breeder.
Someday I want an Irish Wolfhound. They are not very common and only a handful of breeders are out there. I've still been researching to make sure when I am ready and I get a healthy, happy animal. ♥