The green may have been correct. Pumps coming from the factory were painted red if the pump was set up to pump gasoline. Pumps made to pump kerosene were painted green. Your pump appears to have an overhead outlet which usually was the way the gas pumps were made, but who knows who made changes 100 years ago.

Jack Sim

Author, Gas Pump Identfication books 1st & 2nd Editions & Air Meter Identification books
We rebuild ECO air meters and sell parts.