This is a 15" x 6" steel wheel from a mid 80's Chevrolet or GMC truck.  The stamp on either side of the valve stem is K485  9     3 XAH or K486 10      2 3XAH.  Back space is measured to the inside of the tire bead. The center hole is round without "pinch" from the factory.  Good condition .  Two are available with these markings from the same truck.