CrossRoads:
Nanos all use FTDI chip for USB interface, yes?
Don't know, i can't see any separate chip as on Duemilanove f.e.
vendorID/productID is built into the FTDI chip, nothing to do with the '328 that makes the board an Arduino.
See page 15.
Sorry, page 15 of what?
If it's so then i will not be able to distinguish Duemilanove (also uses FTDI) and Nanos. I hope it's not correct and vid/pid are different