When the helicopter is first seen it is a Bell 47G, but later in the sky it is seen as an Aerospatiale/SUD Aviation SA-315 Lama or SE-313/318 Alouette II.
The sound made by the helicopter (Aerospatiale SA-315) while in the air was obviously a dubbed in sound of a Bell 47G. The sound of a 2-bladed main rotor, piston engine helicopter is heard but the SA-315 has a 3-bladed main rotor and jet turbine engine which sounds much different.