I found a Slip-Up in the episode "Pinch Hitters" (where Gary is bitten by a monkey and had to spend the day in an infirmary).

It was when Gary went to a Customs Facility to save animals from dying in a fire. When Gary first stepped foot into the facility, he immediately read the article in his paper that said "Exotic animals die in chemical fire at customs facility."

Gary was not wearing gloves when he looked at the paper... But the camera shot of the paper showed a glove on Gary's hand that was holding the newspaper. The shot stayed on Gary, but showed all of his body, including his hands. He still was NOT wearing gloves!

The one, very short shot of the paper, Gary's hands had gloves on, even though he didn't have any on.