yes that is what I heard and on a fleet that size the fuel savings would have added up to a fair bit
the aluminum should be covered with a clear lacquer to prevent onset of corrosion - it was evaluated by many people in the 80's however most felt/discovered that the increased cost of corrosion related repair work exceeded the true economic savings
I have a Boeing document here which claims that by keeping your plane clean, all seals and doors etc. tight and well fitting and having a smooth (new) paint finish can account for 3% increased drag and save 0.85% fuel consumption each year