I have never traded an FPJ, but in my many experiences in trading in watches to get other ones, I have found that the first thing dealers ask for in many cases, before even looking at the watch, is the guaranty card surprisingly. Then the watch, finally the box. In many cases, the box I had was genuine but not the exact one for the particular watch. No big deal. As long as you have a geniune box, regardless of big or travel size or whatever, that is the main point. Those other items (USB, cloth, wallet, etc.) are all peanuts, or to put it more gently, "icing on the cake", but add no value. While you are not sure of selling, you never know what the future holds.
If the watch is genuine, if the watch guaranty is genuine, if the box is genuine, then the deal sounds worth serious consideration.
Those small items don't add up to anything AFAIK. And also make sure that the sellier is "genuine". That's the thing to watch out for IMO since it is a private sale.
The only concern I have is if this is a long-distance transaction and you cannot see the watch in person. Often times, private sellers go to a boutique
together and try to get some kind of confirmation about authenticity. Good luck. It's a beatuful watch at a more than beautiful price, so continue to do your homework
until you feel good about buying.