Bartruff1,
Inside the rubber boots is grease. Grease is made of soap and
oil, Soap is used to hold the
oil in place. If you are seeing a drip of
oil, which given enough time will make a 3" diameter discoloration on cast aluminium you may have no issues. If your boots are not split, forget about it. Beleive it or not 80% of the grease in cv joint never sees service, how would it nothing pumps it in there. The grease is spun around any by centrifugal force the oil gets seperated from the soap and by capilarry action finds it way out.
As far as the rear end leaking there should be a drop or two every now and then, it keeps the lip seal lubricated. If you aint getting drops on your driveway every single time you drive it you do not have a problem.
If you do take it somewhere make sure they dont try to take you for a ride.
By the way buy GLD hold through september and sell, statistics shows it goes up 5-7% in September every year since 1993.