Small older dog ate pork bones yesterday. Is listless and throwing up. No blood or distended abdomen, but sick.

Swallowed them?

I'd be calling the vet. You could be looking at anything from pancreatitis to a blockage.

or perhaps a shaterd bone has inbeded (punctured her stomach or intestine I would contact a vet and get an x-ray done!

It could even be lodged in the dogs throat.
A while ago I saw a dog that had a corn cob jammed in his throat, it didn't seem to bother him other than he was throwing up a lot.

A lot of dogs can have an allergic reaction to pork as well, if there was meat on the bones it could be a concern. As with pancreatitus as Sariss said.
Pancreatitis would not be an issue if there was no meat or fat on the bone but if there was it could cause an attack.
Small amounts of fat will not have an effect on the dog but a large amount when they have not had anything fatty before can lead to problems.