I don't think Ford used zero's in the numbering system that way. Is there a chance the O is a 8?
If by chance it is CA8271, it could be from May 1928.
and that would be very early for Canada.
I understand that Canadian Model A engines had "CA" prefixes for local sale and for export, they used 3 letters. My 1929 engine number starts with "CAQ".
I'm sure others will chime in here if I'm wrong.
CAO seems right to me but I don't know when that would have been produced. Someone here listed the Canadian letter series and dates some time ago. I just found the thread! Look at post #9
http://www.fordbarn.com/forum/showthread.php?t=211337&highlight=Canadian+engine+numbers