Glock will tell you if you call.
Glocktalk has a serial number sticky
You will have to call Glock with the serial number.
Check with Glock Customer Service through their website.
Mid 80's or so.
Glocktalk.com has an extensive sn database.
http://www.mujglock.com/en/glock-production-date.html
There is a large serial number database on Glocktalk.com. Some books published on Glocks are available that also contain data.
Production date was 1968.
Production date 1977.
Production date was 1976.
Production date was 1977.