Passenger car received a 14" x 5" welded steel wheel made by one of the following companies:
Chevrolet Warren (if made by mid 1963 when GM still made everything on the car), or purchased from either Norris Technologies, or Kelsey-Hayes. It will have a J stamped by the valve stem hole. Offset was 0.56" and inside diameter of the rim is 12.328" for 11"
Station Wagon had 14" x 6" welded steel wheels (stamped JK), and Police/Taxi cars had 15"x 5" steel wheels stamped K from Kelsey-Hayes.
Corvette (that was still in 1964 using the suspension from the full size passenger car), used a 15" x 5½" steel wheel stamped K or a 15" x 6" steel wheel stamped L from Kelsey-Hayes at this time.
Something this old needs to be either X-rayed or at least MagnaFluxed to determine that there are no cracks in these steel wheels due to the bending forces a wheel experiences over time. Kelsey-Hayes still makes new steel wheels for the reproduction market.