Hello Atlantawiseguy, welcome to myBulova. I'm a huge fan of heirloom watches. Watches are so personal, like other jewelry they make wonderful keepsakes. Congratulations on holding on to this beauty. The number on the back is a serial number and does not carry any significance that we know of. "N0" is the Bulova date code for the year 1970. The movement in these watches was noted as Bulova 14EB, it is a 17 jewel Valjoux 7733
The watch is a Bulova Chronograph 31000-W, this model doesn't come along too often, we have a couple in our data base now. Mine is New Old Stock so this gives you an idea what it looked like when new and also a goal to shoot for in restoration:
http://www.mybulova.com/watches/1970-chronograph-6153
The number on the back is a serial number and does not carry any significance that we know of. "N0" is the Bulova date code for the year 1970. The movement in these watches was noted as Bulova 14EB, it is a 17 jewel Valjoux 7733.
I'll send you a private message with a couple suggestions on restoration.
1970 Bulova Chronograph 31000-W