I have a Seagul 4A103 camera and I am trying to date it. I know the history of Seagull stating with the Shanghai 4, but the closest I have come to a reliable date is the 70's. I would like to establish the period for which it was produced. Mine has an SA-91 viewing lens and an SA-92 taking lens and the name is written in Chinese on the top plate. It doesn't take bad photos considering it's heritage.