Can someone please help me identify this watch?

Greetings, I was hoping someone could help me identify this watch -- I've looked high and low, and the closest I've found is ref. # 6405.

Many thanks,

JamesCan someone please help me identify this watch?
the best would be to take the back off and check the
12/19/2011 - 10:16
ref number as many of these poices from the 60s looked similar but with sublte differences