Creationists definitely believe that the dinosaurs were vegetarian even to the point where Tyrannosaurus Rex supposedly had sharp teeth to enable it to eat palm trees. When this vegetarianism ended is up to the creationist. It was either after Adam and Eve sinned bringing evil into all of creation or after the flood - assuming they survived the flood.
Also, their official stand on the creative days was that they were exactly 7,000 years long. Now they're simply wishy washy on the details.