It could be but the brakes pads are fine... replaced not to long ago.
I've (I say "I've" but actually have somebody local who does LR restorations doing the work and me helping) got to bleed the system anyway and for the piece of mind, a few £'s and getting dirty its one thing I can tick of the list... I'm guessing the master cylinder fluids had never been looked at before because the cap was a b*tch to get off!!