The parts catalogs that I have list an early running change for the drum brake part, but no change for disc.
For future searching, I'll add a few terms. This is basic part number 2B257, the Ford term is "Valve Assembly - Brake Pressure Differential", and the disc brake full service part number is C7ZZ-2B257-B in the 1967 catalog, but C7ZZ-2B257-D in the 1960-68 MPC - so there may have been a running change.