Not your alternator, all that stuff turned on put a little more drain on your engine and probably lowered the rpm's enough to come near the low end of the oil pressure sending switch.
My '03 does the same thing. Only once in a blue moon though. Usually after a long highway run when you come to a stop at the end of the off ramp. The needle will flicker a little bit.
Just so you know that is not a full range gauge. Just on or off. It is more like an idiot light, it only reads on or off. If your oil pressure dips too low it will go right to the bottom.
I have read up on the cam synchro probs. I have no squeaking noises etc... Just the blip in the oil gauge.