A few observations:
1. there should be, but aren't, Dominion of
Canada
acceptance marks (a broad arrow inside a "C") on the right side (S/N side) of the frame;
The C^ is there Top left of frame close to magwell swell, but the DCP isn't
2. there should be, but isn't, a cross pennant marking of the barrel visible through the ejection port;
3. the factory applied serial numbers were done using a pantograph which left very neat, evenly space, all on one plane, consistent-depth markings while your serial number is uneven, off-line and not consistent;
4. there is no marking above the "BROWNING - FN 9MM HP" where the "MkI*", etc. stamping should be;
This is an EARLY slide (pantograph engraved left side markings and long dust cover edge) and so wouldn't have the MkI or MkI* originally applied
5. and - significantly (or not) the cam lug is prick-punched to keep it in place in the frame.
I noticed this right away as the Inglis BHP was known to have cam lock bars come loose
All the above, the last point in particular, makes me wonder who, when, and why that was done. One possible answer is also the most likely explanation. That is, as has been suggested earlier, the pistol was made from parts that "grew legs" or were poached from the factory before the S/N was applied and became accountable.
I'm not a betting man, but if I was, I would take 10 to 1 odds on it being a "Lunch-box Special".