I know of one car that was fully rebuilt with new air conditioning and M-1 upholstery seats, painted platinum mist (silver gray) with a blue stripe. This was in anticipation of keeping them after the first order of Budd M-1's arrived. The rebuilding cost was astronomical, and the Railroad used the cost to successfully lobby for funding the second order of (GE-built) M-1's. That was the end of the double deckers. Other double deckers may have been rebuilt, but not the the level of this one. Only one was painted silver.
Of course, there were three different classes of the double deck cars. The prototype (#200, built in 1932) and one were shorter than the rest and were built before WWII. After the lapse during wartime, Alcoa built the remainder of them which were longer than the original two. The cars were entirely constructed of aluminum and electrolysis with some steel rivets posed some problems with the prototype cars. The photos above show subtle interior differences in the classes.
Coach cleaners hated the cars, and swept the lower compartment garbage under the steps. Trainmen disliked them because of the bending and reaching up and down to service tickets. Guys could sit in the lower levels and peek under women's dresses. Guys liked that.
The Railroad later adopted 3/2 seating which gave a conventional coach the equivalent seating in subsequent 1950's Wyer and 1960's Zip car orders.