It has the wrong (green) antifreeze so I want to flush it and replace with the blue.

Now, is this really true? I'm not being argumentative here, I'm just curious (I'm an air-cooled guy who just bought an '84 Vanagon Westy). After reading this I went out to my garage and looked at a gallon of Peak antifreeze I have (for my Chevy van). It says "PROTECTS ALL metals used in ALL cooling systems, including aluminum", so is green necessarily an indication of the wrong antifreeze?  Jeff