Hi Domenico: it would be a unique occurrence of a third rank of jacks for two 8’ choirs in Italy. Imitation of such a foreign custom could happen after 1750, say, but certainly not back in 1699.
Let us put together everything: only the wrestplank looks antique, and is at odds with the rest of the instrument. The faux-inner-outer case, stand and lid are fully painted 19th when not 20th century, the keyboard and the soundboard cannot be Italian 1699 either. At this point, it really looks like a Franciolini or similar fake!
I stand corrected: not even the wrestplank looks convincing. Apart from the square patches to cover former holes (probably for a different set of handstops), its general shape is unlikely to be Italian 1699 either.
Dear harpsichord friends, I have been in Wassenach (mainly to look at piano’s, Italian harpsichords are not my piece of cake) and played the ‘Serafini’ (lot 92). I can confirm your ideas: it it a well regulated, nice sounding instrument, but in no way I got the excitement, or feel of a three centuries old machine. Having said that €14.000 seems a fair price for a nice looking, nice sounding and useful instrument for the music practice. The makers of the catalogue (present in the house) did a very good job, their description does not suggest it is that old, nor Italian. So catalogue text, price and value are pretty consistent in my view.