My father's Gruen watch.

I inherited the Gruen in 2009; it was my father's and he had passed away many years ago, back in 1970. My mother kept and stored it, and since I'd always loved this watch, I was fortunate enough to ultimately inherit it. Doing what light research I have, I believe it to be a Gruen Airflight Precision (Jump-Hours) Mechanical model. The only Jump-Hours models I've been able to view online, however, have all had white faces. The Jump-Hours models were aimed towards military/avaitor use, though my dad was a tried and true yachtsman and top-notch engineer. The Jump-Hours models had a dial which apparently automatically shifted the digits in military fashion; 0100-1200 hours automatically switched to 1300-2300 digits at the appropriate time. It may not even be rare or valuable; it just keeps reminding me of the astounding and rare individual who was my father. I'm not sure I'd mark this item as a true "Unsolved Mystery", but would like to know more behind its history from a watchmaker who may be more familiar with this specific model.