Look here for a picture of the real thing. Based on the symbol on the box, it clearly dates from WWII.
http://www.atlantik-pirat.com/Der%20Atlantik-Pirat.htm
(click on the "Wanted" section, it's the second item listed)
By the way, that website also has photos of the U-jagd stopwatch!
As Pisces said, the reverse side on the SH3 version is adapted from the US model. It doesn't appear that the German version had anything on the reverse side.