Sevo and Encoder identifying

I'm just working out what servos to use with some Gecko 340s,
I have a few old ones lying around which might be a start, however
the jumble of leads on them is putting me off trying any.

How do I tell if a motor is brush or brushless, ie. suitable for
using with a Geckdrive ?

How would I identify the different leads emerging from an encoder, I
have an oscilloscope, but am not skilled in using it.

thanks in advance,

Rab