Welllll...WashPo gives it four Pinocchios
Pence claims he was only joking about the empty boxes. The WashPo article refers to the original CSPAN video, at the 9:00 mark. One of the other guys says the rest of the boxes are empty, and then Pence asks "can I carry the empty ones? Just for the camera?". There's a bit of laughter at that point, suggesting that everyone there got the joke.
Sorry to be a wet blanket. As the Post said,
With so many well-reported articles about the Trump administration’s mishandling of the coronavirus pandemic, why would anyone resort to inventing a story of malfeasance?
Indeed. I watch Kimmel clips pretty much every day and enjoy him, but looks like he blew it this time. It'll be interesting to see what he says tonight about it.