[Identify - Gruen] Grandfather's Watch

Hey all. Long time lurker. Thanks for all the great content on this sub.

Looking for help on model/time-period on this watch:

http://imgur.com/a/xOetw

This watch was my grandfather's. I don't know the time period. He lived from 1919-1990 but I have no idea when he got this watch.

The watch does wind and tick. The second hand labors a bit but moves. No idea about what sort of time it keeps as I don't wear it.

I'm interested in the value only to the extent that it would be worth getting serviced and perhaps reconditioned.

Thanks!