Actually the rucksacks are the same as British 1908 pattern, and were made from 1929 onwards by La Industria Lonera in Barcelona, Spain.
When the group first arrive in the trenches, several can be seen carrying old Swedish army rucksacks. However, these were first issued in 1939 to the Swedish army, 3 years after the time-line of the movie.
The opposition army are referred to as "the fascists" throughout the film. They were called the "Falange" in Spain and at least the Spanish characters would have referred to them by this name most of the time instead of consistently calling them "fascists".