I think you have a TdF - congratulations! My battered ‘71 converted to fixed-gear is one of my very favorite bikes ever! If yours is a 60cm to top, you are especially blessed - there is just something magical about that size TdF. DO clean, repack and cherish the stock Stronglight P3 headset; you may have to open out the headset locknut, but if you do that (and maybe run a brake cylinder hone down the inside of the lovely Nervor metric butted steerer tube) you should be able to fit a Nitto stem in there without sanding it down.

EDIT: you want to keep the stock headset for reasons of stack height - the P3 is 10 mm or so thinner than an old Campagnolo or a new Velo Orange - even the Stronglight V4 used on PX-10 is taller.