103 was the Cavalry unit within a higher formation during the early 1960s: 4/19PWLH - Southern Command, 1/15RNSWL - Eastern Command, 2/14LH(QMI) - Northern Command, XLH - Western Command, were all '103', with the Regular Army Squadron (A Sqn) often adopting and additional "A" suffix, hence 103A on A Sqn, 4/19PWLH vehicles. (The other Sqns were CMF and they apparently thought the Regs needed to show they were different!)
Hence, the LRs at XLH in Booger's images with '103' Unit signs.
3 Cav in 1946 or 1948??
Mike C