Yes, Steve Taubert's book shows it as 1 Armd Bde, which included 1 RNSWL, 12/16 HRL and 6 NSWMR.
I've attached a scan of Standing Orders for Dress (Provisional) issued as Military Board Instruction No. 90 of 1 January 1958 and describes the formation signs.
The original MGO Specification for transfers for military vehicles, first issued in 1950, was also rewritten in 1958.
Keith