From the '60s. German movement, I think. Would need better pics and a pic of the movement. Should clean up nicely. Enjoy.
There is a vintage Gruen forum. .https://www.google.com/url?q=http:/...ND7oQFggLMAA&usg=AOvVaw0o4nAc-oh2HTjE_06Fb94A I thought all the gruen precision were Swiss, but I'm no expert.