There are two versions.
The first without a number on the back and the second series with a number on the back.
There is also a Czech version and a German version.

Appear to be two variations.

One (original issue) with blank backs and some errors in assigning team names (Wembley Lions of UK listed as Wembley Canadians, Wembley Canadians of UK listed as Canadian-based team).

Second (corrected issue) with numbered backs and fixes those team name errors.