It is the period where the game was still finding its footing, one set at a time
For some, that's going to disqualify it from contention, but we've seen stall decks in the past that don't mind sitting back behind a Druddigon and letting your opponent's Pokmon tire themselves out while they build up
Seems youre indeed correct: Quuador: If I read the information on pokeboon correctly: 50 of the blue backs were printed with no number errors

Advanced Search Sets Random Syntax Atogatog Begin the Invasion Call the Spirit Dragons Child of Alara Chromanticore Coalition Victory Conflux Cosmic Spider-Man Cromat Fusion Elemental Garth One-Eye Genju of the Realm Heroes in a Half Shell Horde of Notions Infinite Guideline Station Invasion of Alara Iridian Maelstrom Jared Carthalion Jodah, the Unifier Jodah, the Unifier Karona, False God Last Stand Leyline of the Guildpact Maelstrom Archangel Maelstrom Nexus Marina Vendrell Mass of Mysteries Meeting of the Five Niv-Mizzet Reborn Niv-Mizzet, Guildpact Niv-Mizzet, Supreme O-Kagachi, Vengeful Kami Omnath, Locus of All Primeval Spawn Progenitus Reaper King Rukarumel, Biologist Sanctum of All Scion of the Ur-Dragon Scions of the Ur-Spider Sliver Gravemother Sliver Hivelord Sliver Legion Sliver Overlord Sliver Queen The First Sliver The Kami War The Prismatic Bridge The Ur-Dragon Tiamat Tom Bombadil Two-Headed Hellkite Unite the Coalition Urza, Academy Headmaster

We once received a card that was clearly just dropped into an envelope with no protection whatsoever