What do the numbers under a "R" lens mount mean?

[Calzone]

If you are converting a lens mount on a Leica "R" there is a single digit number witheither a plus or minus sign. What does this number signify? Tolerance of barrel? Tolerance and shims required for cams?...

Thanks in advance.

Cal

 

[sc_rufctr]

Good question but now idea. Can you post a pic of the numbers?

 

[icebear]

Hi Cal,
isn't there a number on M lenses (2 digits though) that indicates the actual focal length like "05" on 50 lens means you have a 50.5mm lens? Something similar with R lenses? Puts should know ...