The earliest known version of Mir rangefinder camera. You can find such type of engravings on the genuine Mir manual guide. The camera from manual has serial number #5924741, and the mine is #5927122.
www.sovietcams.com
Serial Numbers Known:
#5924741 on manual guide
#5924765 SovietCams -> Mirfoto
#5927122 SovietCams