During the tug-o'-war between Pug and the Keystone Cops, Pug's boxing gloves disappear and then reappear on his hands.
(at around 1 min) The sign advertising the Cyclone Flynn fights doesn't appear in front of the town hall when the two hobos decide to pose as pugilists. The sign doesn't appear until about 4 minutes later.
Pug's corner gets very slippery very fast after the second round (where he continues to slide out of this chair). It goes almost instantly from a limited slippery area around his chair to nearly half the forward area of the ring. This possibly indicates numerous takes and retakes, since he is sprayed with water by this supporting team, plus he drinks (and possibly spills, since he seems to nudge the bottle with his foot several times), what looks like milk during the intervals.
Pug has a near-unlimited supply of bullets in the revolvers he fires during the finale chase. He has no capability, because of the boxing gloves he wears, to reload, nor was he carrying ammunition to do so.
Pug is able to shoot pistols without touching the trigger, as he is wearing boxing gloves.