I cannot read the case reference number on the caseback in the photograph. The watch looks genuine with an original dial. However, there was some re-luming done at one point. The dots in the odd numbered markers look a bit sloppy and too white.
The case is in decent shape, not over polished and the blued seconds hands is a nice extra.
gatorcpa
When I first saw the photo I immediately thought it was a ref 2640, but that's obviously not what the case-back says. OP, can you please post a better photo of the reference number, or read it and tell us what it says?