Just to confirm after the fact: When positive-going sound pressure strikes the diaphragm on its 0-degree axis, a microphone is supposed to put out a positive-going voltage.
A bidirectional capsule has two equal and opposite axes--one at 0 degrees and one at 180. The red dot on a Schoeps MK 6 or MK 8 capsule marks the 0-degree axis. The 180-degree axis has identical sensitivity and frequency response, but its polarity is inverted. Thus if you set up your M/S matrixing arrangement as L = M + S and R = M - S as most people prefer to do, the red dot should face to the left. Otherwise you'll get channel reversal in your stereo playback.
--best regards