I need help from the experts here! I have a 2446 last generation with the screw back case. The crown is not signed which I assumed was unoriginal. Recently, I was skimming through the Heuer book and one of the features of the snap back 2446 was described as "now having a signed crown" or something to that effect. The book also touches on the subject of earlier Valjoux 72 Carreras as having unsigned dials. Furthermore, the pictures on this great site show the last generation screw back with an unsigned crown. It seems that there were two iterations of this last generation as some with a "border" around the edge of the Heuer logo on the caseback all seem to have signed crowns and the more plain logo'd ones do not? Holy smokes! I just read this and I can hardly follow it! Does anybody know what I am talking about and can this person shed some light? Thanks!