Barret Stabilizers?

[Sadey]

Looking at a boat that has them installed but the owner is not sure if they work. Neither is the captain who runs her. The boat has not left the slip other than back and forth to storage or for a sightseeing cruises in the last bunch of years. Are they obsolete or still serviceable? How can one tell if they are working if it’s calm seas? The surveyor I was considering on using hasn’t had many dealings with stabilizers at all. Obviously I’m looking for other surveyors who might have better knowledge but thoughts from any of you experienced folks? This will be our first Hatteras so we are just babes in the woods. The boat in question is a 1988 60MY with 892’s. Thank in advanced for the help!