I have removed the Weems & Plath Barometer from our 36' Classic.
I believe according to the serial number that it is a 1987 or 1988 model Atlantis Barometer.
New, they sell for $439.00 on the Weems & Plath website.
I really have no idea what its worth, but it works just fine and is in pretty good shape for being 30 years old.
I had all of my light fixtures professionally cleaned and they looked amazing, and this can be cleaned as well.
Make me an offer if you are interested.