Interesting question.
As to the pre-1930 cards, no. Those actually had backs with printing and copyrights, so there is no mistaking them. Postwar, the boxing basically mirrored the format changes of baseball, except when it doesn't. As best as I can figure it, ESCO switched in new fighters as they rose through the ranks and dropped older fighters as they fell out of favor, so there are all sorts of SPs and SSPs over the years.
In terms of Canadian cards, there were Canadian boxers. They are a quantum more difficult to find than the Canadian baseball cards. I've seen them in pink, green and blue. There is even a Canadian Joe Louis from the Champions series.
Here's a blue tinted Canadian Louis
The Canadian Champions Louis
