The breeder should have docked the tails at 3 days old. Since that didn't happen, I would think it would be somewhat cruel to dock them at 8-12 weeks when most people get their pups. That's the AKC standard.
More and more European countries have anti-docking legislation, so it's illegal to show a docked Pembroke (natural bobtails are fine, of course).
Different countries, different breed standards for tails. I think they're beautiful either way.
Photo of a Pembroke Welsh Corgi Champion from Sweden: