I hadn't realized the large gap between the movement and case numbers, or that this Cal. 52 was so early an example. Difficult to see on an iPad.
I don't mean to be contentious, Tonny, but I disagree when you write that "Could be OK since in these years, lot's of calibers were made but stayed on the shelves unsold, to be used in watches some years later." It's theoretically possible as a one-off exception but I have not seen any movements from say 1890 to 1905 cased much later. I also have not seen any early (1890s) Calibre 52 with a dial with Arabics, let alone a dial of this color. These dials were from a later period than the early 1890s.
I didn't mean to imply that the case wasn't original (however, they weren't made then in Schaffhausen I believe) but only that the screw around the pusher shows a non-IWC factory, later revision to the case.
But given that, plus the incongruity of the dial to the movement, plus the differential of the dating movement to the case, I would think that there's been some transplanting here that amounts to a marriage. Sorry to say that!