Just to complicate things, when I joined up in '63 the rank structure still included the "upside down" technical ranks and these were based upon time in post plus passing the technical examination. This established your pay grade and technical competence. A Junior Technician could sign for his own work but not that of anyone else. A Corporal and above could sign for his own work or that of a junior rank who he had supervised. The Technician ranks had no disciplinary authority perse, only trade authority.
The right side up chevrons were "command" ranks and carried disciplinary authority. These ranks were earned on the basis of performance assessment. So, it was possible to be, say, a Senior Technician on the basis of technical qualification and then be promoted to Sergeant on the basis of your annual assessments - or from Corporal [or even Junior] Technician to Corporal etc. Corporal Masterson therefore appears to be a tradesman at either the J/T or Corporal Technician level holding the command rank of Corporal.