I am a first time poster, but long time lurker of this wonderful site, so first of all, thanks to everyone for all of the incredible information and pictures that are posted here daily! I had been on the hunt for a very early black dial Carrera after having read Eric Wind's very informative and comprehensive article addressing the earliest known Carreras. I was very fortunate to have located a 3647N that I believed was among the earliest made and reached out for assistance to several members of this amazing community. I owe a debt of gratitute to Eric Wind and Mark Moss for their very thorough and thoughtful analysis of this piece through multiple emails. As well as to Robert R. and James L. for their help too.

This 3647N has the marking to confirm that it would have been among the earliest two register Carrera 45s to hit the market. It has a swiss only dial, the serial number is engraved at the six o'clock position and is 5456X, the movement bridge is engraged Ed. Heuer, as is the inside of the caseback. I would be curious to learn if there are any known 3647Ns with a serial number earlier than 54570 other than this one. Here is a pictures taken today upon arrival:

JRock