The serial numbers are in vastly different ranges. The new one has a meter. I never did understand why Leitz/Leica chose to give it the same model designation.
Possibly because all Ms after the M7 are likely to be digital (that's pure speculation), and if so because a lot of other M-combinations are variously misleading (MA, MB, MC, MD, ME, MF, MG... MH is the first one that doesn't sound like something else, but after that there's still Michigan, mark, millilitre, millimetre, Minnesota, Missouri, metol-hydroquinone, mister, ms., mount (or Montana), an Olympus camera, Motor Vessel, flash synch, possessive pronoun, East German motorcycle (Motorradwerk Zschopau).
All right, MP is also Member of Parliament, which one could take as misleading and insulting, and Military Police, but it's (a) well established and (b) better than many of the alternatives.
Guess who's looking for displacement activities to avoid further research on whether it's legal to park motorcycles on the sidewalk in Hungary, and similar information of great use to motorcyclists but limited appeal when it comes to doing the hard research.
Cheers,
R.