ORIGINAL: RCKen
No, you can use just about any brand servo you want. There are a few small considerations that may need to be taken, but they are minor. Like the tab on a Futaba servo may need shaved off. Or older Airtronics servos may need wires switched. Refer to the attached diagram as a reference.
Ken
So could I also use any receiver I wanted as long as its the same frequency as the radio?