I would start with a flush and bleed before going any deeper. The problem I've had with this particular MC was with the piston binding, not the seals leaking.
It's a pretty easy unit to rebuild. Get a service manual, exploded view (parts manual) or take pictures because you can easily reassemble it backwards (pls. don't ask me how I know!).
You'll need some internal snap ring pliers preferably with a long skinny nose since you'll need to reach down inside the bore to release the snap ring -I modified mine courtesy of my Craftsman grinder. Compressing the spring slightly as you squeeze the snap ring helps a lot.
A seal pick to reach down inside the bore is helpful also, as is a little patch of ScotchBrite and some brake cleaner to gently clean the cylinder.