I can assure you that the Victorian Government "M" registration number
plates that were used on some of the last buses purchased by the M&MTB
were NOT mauve, but RED lettering on a white background - albeit a slightly
crimson shade. This style was introduced at the time of the Hamer
Government's adoption of the Green-on-White "Garden State" number plates.
Prior to that, the "M" rego plates were White-on-Red, although in this case
a browner shade of red. Many of the Board's ancillary vehicles had these.
Attached are a couple of photos from the TDU Archives, the Black-&-White
image showing R10 with the White-on-Red plates (but with the even older "V
*" prefix), and the colour one, of the City Circus opening debacle, showing
a newer R10 bearing one the plates described by Ronald Besdansk.