[Chris Haynes]

Commercial vehicles were restricted to only one standard color, Rock Moss Green upper with Black lower. In Sept 1930 Phoenix Brown, Menelaus Orange, Rubellite Red, Pegex Orange, And Blue Rock Green became available. In June 1931 any Standard color could be ordered. Colors for Deluxe vehicles were not available. So to be correct you need to determine the month of the build. The serial number will determine the month.
When in doubt refer to the club's Judging Standards & Restoration Guidelines.