Firstly, this thread is not intended for inquiries. You should get more feedback if you start a thread about this watch. Secondly, original box, papers, strap, etc. can add value but many of these apparently "full-sets" have been put together from disparate components. Lastly, the condition of the dial is of the utmost importance when assessing value and this one, though original, is somewhat worn. IMO, 6k EUR is too much for this piece, even if the box, papers, and strap were original. Here is a similar piece for a more reasonable price:
https://www.ebay.it/itm/Longines-Ch...934660?hash=item4200016bc4:g:iXUAAOSwqrZcSOVO