if there is a difference, one can choose to overwrite one with values from another. so it is anyone's guess what happened there. this is why making backups etc is important before touching something. if you are not 300% sure you can restore everything back the way it was, do not make the change.
going by the label ,this is a KR150 (not KR150-2 etc.) and it is supposed to have a spring type counterbalance. if you posted picture of the actual robot arm and the wrist label, we may offer a tip, otherwise contact KUKA, they can look it up in 2min and no guesswork is involved unless arm was modified after robot left the KUKA factory... such changes used to be somewhat common when changing reach (installing wrist extension) and increased reach normally means derating (lower payload). if such modification was done by 3rd party label would no longer match actual configuration.