Having attended four summer camps for Army Cadets 1968-1972 I was well acquainted with the Halifax Rifles cadet corps; I have never seen a brass badge; both King's and Queen's crown versions were worn; some were white metal or pewter cast and have seen embroidered badges for officers'.;
my suggestion is that the brass HR badges may have been sales samples not approved by the parent militia unit.
best regards, Ronald LeBlanc