Before Black Louie throws the third knife at Larry, we see him against the wall with three knives already on him.
The fork on the Governor's hand changes from left, right, and left again when Rita brings the Stooges into his office.
The knife target on the wall at the pirate's den mysteriously changes to a stick figure with hair.
When Black Louie gets knocked out with a vase from Rita, the actor accidentally knees Curly and he makes a pained expression.
During the end fight scene, Curly's glasses almost fall off twice when he does his gobble to the camera.
When Curly says the line, "Because a hot stake is better than a cold chop!", Larry is seen mouthing parts of it.
Curly stops too early with the lollipop when the Governor mistakes it for a ruby.
When the Stooges say "West wall?", it is clear that Curly was going to say something else.
The jackhammer that the Stooges are using, while making lots of noise (sound effects) does not seem to have any moving parts. It does not move at all. Since this short is set in 1672 and the jackhammer was not invented until 1806 and the electropneumatic or rotary hammer much later (not to mention electricity via wall outlets).
Curly's yelling when he falls upside down on the chair is obviously dubbed in as his mouth does not move.
Moe chuckles when he challenges the guard to push him again, but his mouth does not move.