Yeah, look at the gearbox for cream-colored oil.
Check the small rubber boot where the speedometer cable enters. If it is dry and cracked, replace it. It is a entry way for water into the gearbox. You might even want to cut a length of large diameter heat-shrink tubing, and put it on the speedo cable before the boot. Then after the boot is in place, draw it down over the top of the boot and heat it up! One of the nicest solutions I have seen.
Watch your tires for dry rot. I have yet to hear of anyone actually crashing due to old tires, but then, I don't talk to a lot of riders.
Have you had the rear wheel off, yet? It is relatively easy, and you get to check the wear condition and the state of lubrication of the splines, as well as the brake shoes, all at once.
If the splines are razor-thin, you probably don't want to take that ride.