Looking for replacement pancake air tank

Last couple of trips I have noticed that the compressor for my air horns cycling. The tank is mounted on the firewall on the drivers side. It appears to be a 2 gallon tank. I believe that since the tank is mounted on the firewall I have no drain on the tank. I believe the water sits on the bottom of the tank rusting away.

Not sure who Fleetwood purchased their air tanks from back in the 90's.

I'll try & get some pictures posted.

Thanks.