I’m not sure whether this is correct or certain. There have been discussions about this here before. The crown/RC stamp is considered to represent “Revisions-Commission”, an acceptance body at Erfurt during, not after the war. The stamp may represent repairs or reworks before guns shipped out after final inspection. Nobody seems really sure.
This does not appear that unlikely. As a possibility, you’ll find that over 100,000 Germans emigrated to Brazil between 1920 and 1939, with more to neighboring South American countries, and considering how many of these WW I Lugers were floating around Germany during that time, it is not at all unlikely some came along stuffed in suitcases.