When Moe says, "I'll murder you!" after Shemp smashes a bowling ball over his head, his mouth doesn't move. Same thing is later when Moe yells, "Give!" right before the Stooges trash the officers with dishes, and a few seconds later when he says, "Oh, a double-crossin' rat!" as he's about to throw the plate of spaghetti at the officers.
While Larry's thinking aloud how to avoid his taxes, he slices the loaf of bread diagonally in one direction. Yet when the bread is fully cut and he stretches it out like an accordion, it is cut in the opposite direction, revealing the substitution by the prop rubber loaf.