'97 to '06 are the TJ years. LJ is the common moniker for the TJ Unlimited built between '04 and '06 though i think they were designated TJL by Mother Mopar.
The TJ is the short (standard?) wheelbase Wrangler (1997-2006).
The LJ is the long (104") wheelbase Wrangler.
My 2005 Unlimited Rubicon has the LJ designation stamped on several body component tags. The front grill radiator support on mine is actually stamped TJ/LJ (as it fits both wheelbase version of course).
The LJ was available from 2004-2006
The LJ Rubicon was available late 2005-2006.
Only a little over 12k LJ Rubicons were made across both years.
That's my story and Ima stickin tooooit.