Question about installing and mounting an Encoder

[Jakenan]

After a long search, I'm still left with some questions. We are attempting to use encoder for motor controlled arm. We've done previous test on a vex pro gearbox with an encoder. Our arm uses a Cimple Box and I understand that the same encoder can be used. We have removed the encoders from the vex pro and will reuse them on the Cimple Box. My questions are can we place the used encoder on the cimple box and do we need an additional mount?