All over blue for non-gangwayed hauled stock until the last was withdrawn (from the GN lines) in 1976.
Also initially for all DMUs except classes 119-120, 123, 124, 201-203 , which went straight to blue/grey (althogh I think i recall seeing a class 120 with one all-blue power car)
EMus were initially all blue, but those with gangways (BEP/CEP, BIG/CIG, VEP, REP/TC) went to blue/grey very early (some were delivered new in that livery). Not sure if any AM9 was ever all-over blue.
If I recall correctly, 312s were the last to be deliveered in blue, and 313s the first in blue/grey.
Blue/grey for all units started to be applied in the early '80s.