Pretty sure they are, for example at the begining you can hear the sound of the vision mode changing and the increased heartrate from the scene where Dutch is running through the jungle and the Predator is directly behind him, just before he slides over the cliff. The roar when the Predator is knocked back by the Predalien is taken from the original Predator medicomp scene.
It's possible that these sound effects are used in the final movie but I'd hope the Strause brothers wouldn't be so ham-fisted with recycling the sound effects.