Yes, pin 1 (orange / white) is the positive and pin 2 (orange) is the negative. The chip is looking at line 1 for the signal and comparing it to line 2 to detect the high or on signal. Since both of these lines are high impedence, any noise induced on one should be duplicated on the other so the compare between the two should have the same difference. If you reverse the lines, then all it sees is zero and the negative going high is considered noise and is ignored.