The Hughes/MD 500 (369) helicopter has a jet turbine engine that uses Jet-A fuel. Filling up with auto gas from the tanker truck would not work well. The engine would be damaged and would not get very far.
The call sign heard for Walker's MD500 was "329 Foxtrot" which would be incorrect since the registration number is N9103F. It should be "9103 Foxtrot"
Walker was flying with a microphone in his left hand. The left hand is always used for the collective, so in this case a co-pilot must have been used. Normally helicopter pilots would be using a headset with attached microphone.