Given the distributed nature of the Nepal Francotte component manufacturing process then centralized fitting and assembly, a number of differing "features" have been detected among them after careful study such as:
Long/short nocksform (yours is long)
Cross pin/No Cross pin in the forearm (yours has a cross pin)
Cocking indicator or weld closure/no indicator or weld (yours has a weld closing what was originally a cut out for the indicator)
Thumb rest or no thumb rest - this feature appears to have been fazed out early and is pretty rare to find
Sa or Sri inscription on the lever (you have "Sa," - again, suggesting early manufacture)
Brass versus iron butt and nosecap
Locking screw/no locking screw (you didn't post a left side view of the receiver so I cannot tell)
The features above are not consistent to "patterns" and are found in a multitude of with/without combinations although most the later production seem to have dropped many features probably to simplify and speed manufacture (why bother carving a thumb rest if you could do without?)
You internal assembly is stamped च - Ca and there should be a number stamp near it or on the same surface somewhere. I do see a mark in the upper left of the photo, obscured by grease - possibly a "7." If you have a clear photo of the assembly I might be able to pull out a serial number for you. You likely will find the same mark on the underside of your lever, and on the bottom rear flat of the receiver where the lever hides it when closed.
I'm in agreement with you that the crossed cannons are a recent stamp and probably not an arsenal or Nepalese Government mark-at least no one has noticed or mentioned one anywhere that I've ever seen.
Congratulations on obtaining one of the earlier and rarer versions of the Francotte. I'm speculating you have serial #CA-7, but it would be nice to have a confirmation.
Cheers, Vern