Nice watch and a great heirloom, the waffle dial is very stylish. Needs a little attention, but I'm sure it will clean up nicely. I have definitely seen this reference before but can't recall the number at the moment. As noted above, if you have it opened, the information will be readily available inside. Without trying to narrow it down very finely, I'll just say that the value is in the $500-$1000 range depending on many variables. If you are selling, assume the low end. Insurance, use the high end.