A few months ago the same seller offered a comparable dial for the Autavia 2446, however a version in silverburst ( like Carrera) with black subdials ( no additional text though like your's ). I hesitated whether I should buy both. Finally I only bought the "SN"version.I received it and it has all the properties of assuming it being authentic. I was ever so lucky when David Devos sent in a photo of his friends' Autavia with exactly the same SN dial one week later !

I contacted TAG Heuer on your's as well though then and I was told it may have been a sample from a small batch of watches which was custom made for a specific client. A pilot's academy maybe or a association of aerial chartmakers or photographers. They were not sure though. Too far back for the people who are in the service dpt now.

Hope this helps.

Ron