I do not know how to describe it. I think it should be 6394Q if only consider the shape of the antique watches . Because it with a calendar window.
Q as in Quantième = date in French.
but in the case carved ref.6394. I judge this is a assembled watch.
Another case I have seen. in the case carved ref.6394Q ，but it without a calendar window.
I think if you want to buy a antique watches ,first at all you should have more knowledge reserves.I was lucky,with little knowledge when to buy my the first antiques V&C . it ia a original one
thank you tick-talk
You do not have a front facing picture of the watch you are questioning, which makes it a little more difficult to compare.
But if I draw a straight line from the center of the 12 o'clock marker to the center of the 6 o'clock marker, the line seems to run through the center of the Maltese Cross and I see no problems with where it runs througn the word "Automatic".
of the Q doesn't suffice to deduce the case-back doesn't belong to the watch since its birth, imo, only the ledgers may tell.
Several are the elements of a dial which need to be evaluated prior than those, a good picture taken from the front would help :-)