It's not so much a temp thing on ribs, as it is a feel thing. If you bend them and the meat begins to crack, they are done. If you poke between the bones with a toothpick or probe and it is firm, but buttery they are done.
It's really tough to get an accurate temp on ribs due to the low amount of meat and the proximity of the bones. That's why most folks go by look and feel instead of temp.