Aluminum is a good electrical conductor, but not as good a copper, however, for some reason it doesn't work well for shielding. Probably the same reason that lead shields the best but I wouldn't recommend putting much of that on your gyro.

Again, before you fly, with everything powered up, tilt the gyro side to side and watch the servo till the head. If it appears to be smooth and no jitter, it should be OK. Also, tilt the head side to side from your transmitter and look for anything unusual. If it appears smooth, I wouldn't be concerned.

Phil