Experience gained as a Reserve Officer can be used to gain previous experience points on the CS exam. I know its not a lot but it could be enough to break a tie which could mean a big difference. As far as auxiliaries I really don't know if they qualify for the extra points I've heard both yes and no, I would call CS to find out.
To have points counted as an auxiliary you must have performed work in a paid status. All of your auxiliary hours don't mean squat but if you work paid details that will count. I think when I submitted mine I only had something like 450 detail hours that counted toward preference points, well it didn't even add up to a point it was more like 0.04 and they rounded down to the nearest number so it didn't help at all.
Unless you have a ton of detail hours as an aux I wouldn't even bother. Now reserve officer is a different story especially if you are working on a regular basis.