 you  can see these in the "making of the Golden Eye" as used for the  stunt. Clearly they are not meant to be there by script, as it is a  place deep in Russia that doesnt have western European vehicles,  and moreover the facility seems to be locked before his jump (Bond  has to unlock the gate to enter). The shot of the dam right before  the jump (no more then couple of seconds) shows the entire dam  empty.