While Perry and Dick are pausing before entering the clothing store to buy Perry his suit, a blue 1949 Monarch drives past them in behind. Seen as a drive by car in the beginning of the movie as well, Monarchs were only made in Canada.
When eating in a Kansas diner Hickock swigs from a bottle of beer; alcohol was only served in licensed taverns at the time.
The grain elevator behind Perry and Dick when they rapidly back up to leave once Dick has pestered the woman at the diner, shows Balzac on the side. This is a town in Alberta, Canada.