ancientaviator62. It may well have been later. I remember that he was in blues and I went overseas in 1965 and did not return until 1967.
From Wiki for what it's worth.
Junior technicians are qualified to work alone and supervise untrained airmen working within their area of responsibility. The rank was introduced in 1950 as part of a new grading system for technicians, wearing a single point up chevron. In 1964, when the grading system was abolished, JTs were retained, their badge changing to a four-bladed propeller