In my experience you don't always find a stripped servo unless it's under load, and even then the gear could be almost gone, but could be intermittent. So, to see if servos are stripped, which they probably aren't, fire up your radio, turn the airplane on and work the control surfaces.

Even if you find a stripped servo it's no big deal, the gears are cheap and easily replaced > as long as you keep track of how they came off it's a piece of cake. I draw a diagram on a piece of paper and put the gears on it, in order as I disassemble. So no worries on stripped servos.