I only see NC6 referenced in Corlorrite's own website. All other references, including BMW's own labels and docs, use B50. I highly doubt BMW would purposely confuse themselves by using the same B50 code on both automotive and motorcycle application and for them to refer to different formulas.
Just bear in mind though, that even if it is the correct formula, each batched of mixed paint will quite possibly be slightly different. Besides mixing ratio errors, the OEM paint could have faded somewhat and changed hue or saturation. This sometimes presents a problem in automotive refinishing, where a spot repair requires the painter to "blend" into existing painted panel. It's customary for the painter to bring in an existing body panel, say the fuel door, to the job shop for verification and "tinting" to match, if necessary. However, painting motorcycle panels are just about always an overall job. The parts are small enough that it's easier to repaint the whole thing. So precise color match is less of a problem.
If you are buying touch up paint for small rock chips, it won't matter.
2014 K1600GT Sport