Yes, you did have to have the expansion to get the extra avatars, but it's my understanding that the job itself was in the original release of the game. If you have proof to the contrary, I'd love to see it.
05/16/2002: FFXI PS2 goes on sale, Service begins!
The names for the twenty worlds were revealed: Bahamut, Shiva, Titan, Ramuh, Phoenix, Carbuncle, Fenrir, Sylph, Valefor, Alexander, Leviathan, Odin, Ifrit, Diabolos, Caitsith, Quetzalcoatl, Siren, Unicorn, Gilgamesh and Ragnarok. On the first day of service, there were so many access requests that the servers were down, and disconnects were common. This was completely fixed by May 19. Due to the loss of service, free play was extended past the end of May until the end of June.
04/15/2003: Samurai, Ninja, Dragoon and Summoner were added as EX jobs. Only Summoner could be attained without installing the expansion, but players without Rise of Zilart would be limited to Carbuncle.