The two-part episode sequence Ice Queen (2003) and Meltdown (2003), aired in the spring of 2003, was the pilot for NCIS (2003).
Gibbs is correct in saying that he doesn't have to offer Rabb any military courtesy, such as saluting him or calling him "Sir". Though they're employed by the Department of the Navy, the vast majority of NCIS personnel are civilians, and thus aren't subject to the military chain of command.
Interesting that Donald P. Bellisario gave both John M. Jackson and Mark Harmon's onscreen characters the middle name of Jethro. This is a rare episode in which they both appear.
During Gibbs' interrogation of Rabb, after Rabb smacks his hand against the one way mirror, Blackadder mouths the word "asshole".