The "M" means that it is auto-aperture and has the pin to stop down the aperture on most M42 film camera bodies. To the best of my knowledge, no Helios-44M is multi-coated (
Edit:, see comments below...I was mistaken). If a Helios-44 variant has multi-coated optics, it is prominently labeled as "MC" on the lens front.
All that being said, I think you are really going to like shooting with your new Helios-44M. I have been very happy with mine and its image quality.
Steve
Last edited by stevebrot; 04-22-2012 at 11:10 AM.