Late '80's at a guess.
2 things jump out:
1. The cowling when unsupported and not secured does appear to be closed.
2. The lower cowling catches, in requiring the hooks to be manually engaged seems like a gotcha, if not correctly engaged on a cold wet night, lying on your back at the end of a shift with a take-off time to meet.
I guess the hold open device was not at that incorporated on the aircraft.