A = January, M = December, the letter I is skipped / 7 is the month ~ 7K = July 1967, or 1977, or 1987, or?

DOT: US Department of Transportation. DOT numbers will be found on lamps, tires, glass and a gazillion other parts.

If the glass was actually made 7/1967 (I have my doubts), it most likely would have been installed on a 1969 Econoline (intro'd 2/1968).

Hinged ('pop-out') glass like this was used on the right/left side doors and back doors of 1961 and later Econolines, but I don't recall this glass being curved.

The handles were chrome 1969/74, 1975/91.