Just to go back...XH = GM Overseas Operations code for New Zealand. It related to the two plants, and then around 1955 it changed to 'NZ' for some reason!
It appears as though XH8448, or the equivalent in South Africa...XG844x, indicates a model number. GM of Canada tended to differentiate models by destination, with 'X1' to 'X9' used as a suffix. In this case the stamper has added '-' then the sequential number starting with '001' which is interesting, since it could have been '1', and it looks rather neat. However whomever did the stamping varied the date format, between 'US' and 'British' styles.
Also noteworthy is that the 1943ish-on GM of Canada plate change (there was evidently a running-change, e.g. with the C60S 1942-3 Models) brought in a new plate with 'DATE OF M[ANU]F[ACTURIN]G' instead of 'MANUFACTURED' or 'ASSEMBLED'. This plate design was not used post-war, and was evidently restricted to CMPs unless anyone knows of a 1943-44 MCP with one?
