Help - Can you I.D my Grandad's watch

[RichieB]

Hi all, newbie here. I was left the following watch by my Grandfather when he passed away and I'm trying to establish some more details on it after looking through loads of Rolex websites and not managing to come up with a match. It's a medium sized gold Rolex with the word "Precision" under the ROLEX logo. It has 2 hallmark stamps on the rear of one of the four arms which attach the leather strap to the watch, which are too small for me to make out. It also has the smaller seconds dial at the bottom of the face.

https://plus.google.com/u/0/photos/1...64221437574258


It was given to him in 1965 as a long-service award to him from the Swan Hunter Group and has such inscribed on the back. It has the original box and guarantee, but although the guarantee is dealer stamped - it does not include watch no or details/description or model. Do I need to open the back of the case? I should mention that the watch has stopped working (possibly after over-winding on the wrist) and the face needs a clean. Any ideas as to potential value?

Hope somebody can help.

Regards,
Richie.