My understanding was the cockpit canopy was open in case of ejection at slow speed and low altitude.
Egress systems back then were not quick and if you attempted ejection at takeoff speeds, the canopy may not cleanly separate and/or may not separate fast enough, to prevent the pilot from going through the glass and possibly losing his kneecaps. That is what I seem to recall in Life Support school a few years back.
He landing ... notice the speed brakes and leading edge slots deployed
He landing ... notice the speed brakes and leading edge slots deployed