The permanent enters as a 7/7 Dinosaur creature that still has its other types and abilities; it doesn't enter and then become a 7/7 Dinosaur creature. Any triggered abilities that look for power, toughness, or creature types to determine whether or not they trigger will see those characteristics.
As a historic permanent you control enters, it becomes a 7/7 Dinosaur creature in addition to its other types. (Artifacts, legendaries, and Sagas are historic.)
