Yes, just make sure the servos can handle the voltage.
The Berg can handle it no problem , I ran them on 2S Lipo/8.4 volts all the time in my indoor models.
I always just cut the antenna short for the foamies, but you don;t need a lot of range in the gym
In my gliders I left them full length and let the excess dangle.
Just be sure to do a range check with the sticky antenna before you fly.