[jen729w]

The MP is a “regular” film camera. It’s the final Mx in the film line, my understanding being that the ‘P’ stands for ‘Perfection’.

If the ISO dial on the back were metal and not plastic, it may well be perfect. I’ve heard of people switching out the dial from older M4/5/6s.

Source: I have one.

[Darthy]

Well, the "M" in the regular Leica M-Series means "Messsucher". The M in "MP" means "mechanical" (as in "mechanical perfection"). So based on that one could argue that the MP isn't part of the regular series :-)