During the first rescue, squad 51 is seen leaving the station. When the camera angle changes from inside the cab of squad 51, there are louvers visible on the hood. That is from the earlier model Dodge trucks from the late 60's. Squad 51 is a 70's model and does not have louvers on the hood.
The key that broke in the squads ignition was round, Dodge ignition keys from that era were shaped like a pentastar.