Hi Lyn,
some other info.
According to my data base your pistol has been made in the 1974/76 period. Unfortunatly I cannot be more precise for the moment. Maybe you have the date written in the test target.
Your pistol is a 06/73 model with a particular pin that go trought the frame to block the grips, doesn't it?
Let me know.
Ciao
Mauro