No. In Final Fantasy Tactics: The War of the Lions, the only Knights are the Knight, Dark Knight and Onion Knight job classes. No Special class bears that name either.
(from another user) In the original (PS) version of Final Fantasy Tactics, Wiegraf was known as a "White Knight". There may have been another (I can't recall if Delita was a White Knight or a Holy Knight in later chapters), but it was limited only to non-player characters - you could never get it outside of use of the gameshark (which would alter the affected character's appearance to imitate Wiegraf or Delita depending on the code). In the War of the Lions (the PSP revision) it seems that they have been edited out and replaced by the Holy Knight Classes (at least from what I understand from the user who first posted, I can't say for sure myself) - possibly having replaced them with Holy Knight.