While older vehicles may have had a keyed ignition switch, all it did was provide a completed circuit. The starter switch was mounted in the floorboard and operated by foot.
Nearing the end of the film, Brad is seen in the stalled truck with both hands on the steering wheel when suddenly we hear the sound of the failed starter and ignition.
The lion that was shot with a gun was a female, but the lion that Bomba mercy kills with his spear was a male. Also, Bomba's spear has no blood on it after he stabs the lion.