Supermoto wrote:
If you don't need to sell it, get it serviced, get all your research and opinions from the pro's on these sites documented, put it in a cupboard until the economy picks up (5 - 10 yrs ish) I have bought an identical model to you but yours looks in better nick than mine "1969 Navitimer just bought" consider changing the strap, leather ones around £140ish from an AD. I think the red box on the face and the sliderule make this quite rare and therefore perhaps more sought after for a 4rth Gen Navi.
It's a lovely looking watch with a great history, there are some very learned fellows on here who will help you and good luck with which ever way you go
Going off the sometimes heated discussions that appear on this brilliant board I thought I had better apologise

for this old comment of mine, I can see now how it could have raised your suspicions. It was made in innocence as I am documenting the restoration of my watch so that it has a history to pass on to my son.
Thanks Phil AKA Supermoto