Hey Stan

the servos you saw i think they where in ailerons.
there where the aluminum L mounts hold the servo..
becouse Skymaster hardwear provide too short M3 screws the only way to do work if you bord to go out and get long ones
is to install the servo direct with out the rubber.

jets dont have promblem with vibrations so servos life will be the same with out them and they will do fine!

i personaly always use the the rubber and longer screws with safety nuts on the back cose threating in aluminium can be soft..

this way when i finish i never go back to them

my 2c