This is how they break down according to my newly acquired Canadian Maintenance Manual for 1948-51. Note that the decoded years fall outside this range. If desired I can scan the information and pass it along to this site.
case a:
7 1947
1 Chev
1 1 1/2 Ton
3 Wheelbase 137"
3 Cab on chassis
397 production serial
case b:
4 1954
1 Chev
4 3/4 or 1 Ton
3 Wheelbase 137"
3 Cab on chassis
4153 production serial
