I have an M6 serial no.1676340 with ERNST LEITZ WETZLAR GMBH engraved on top to the rear between rewinder and hotshoe. I have had constant trouble with the rangefinder focus slipping. Had it serviced by Leica UK and Leica Italy and another guy with Lewis in London. It just keeps slipping out within a month or two of usage. I am not a guy who chucks cameras around. I heard that Leica had cameras made in Canada a few years ago and that they were not up to scratch. I wonder if this is one of them. Regards Declan PS excellent site.