The sales staff is on crack. Or just embarrassed when they don't know something and are just making sh** up. The six bit coding 1) communicates which lens is being used to the M8 body (and as KEN says, id-ing the lens in EXIF data) and 2) tells the sensor how to compensate for light fall-off with wide-angle lenses. You can do the coding yourself with a sharpie, if you feel you must. Since you only have one lens, it would take forever to wear off. BTW, I would recommend getting the UV/IR filter for this lens. It will make color correction a lot easier.
BTW: Leica said for years and years that they couldn't make a digital RF, because of unacceptable optical vignetting with wide angle lenses (sensors=need photons hitting light sensors "head-on" as opposed to obliquely (acceptable with film), which was a characteristic consequence of the RF WA lens designs). Also there were different amounts of optical vignetting with different wide focal lengths and this gave the mechanical/optical engineers headaches. They hit upon a software fix for this vignetting, but the amount of required correction is different with each lens design -- this is why the 6-bit coding was born, to tell the camera how much to compensate for light fall off in the corners in a lens-specific way.
