From the crimp shape alone, I would say that the K & C headstamp and the F.M.G. headstamped rounds were not made by D.W.M. The neck crimps are a different shape. Further, on my screen, the date on the F.M.G. round looks like it is from the early 1950s, perhaps 1952 or 1953. It is hard to read on my screen because of abberations right over the bottom of the date. If it is from the 1950s, we can rule out manufacture by either Keller & Company or DWM. However, it is bottom that both of the two, the K&C and the FMG, were made into dummies from fired cases at the same factory, perhaps at F.M.G. Those factories don’t throw much away and it is not at all impossible that they had brass even as old as the K&C round in their storage bins waiting for some use or another. The neck crimps (just above the shoulder) are oddly positioned anyway, and so identical in the two, that I would agree they were made into dummies at the same factory, although probably not originally manufactured by the same one, due to what appears to be a very wide date discrepancy, again as view on my screen.
With dummy and blank ammunition expecially, there is never any guarantee, without added information, that the cartridge is as it left the original factory headstamping the case. Of course, sometimes the headstamp also is no guarantee of where the case was made. Well-known headstamps for Perú and Honduras in 7 mm Mauser caliber were made in Mexico, for example. That would not be true in the case of the Keller & Company headstamp, however, to the best of my knowledge. I would say the case as originally made was their product. I am just not sure about the form in which it “was originally made.”
Please confirm the date on the Chilean cartridge.