When I drained my tanny today to drop the engine the magnetic plug was covered in this really thick sludge, almost like grafite grease and had a bunch of little metal particles stuck to it. Is this something that a 30 year old tranny will have or should I be freaking out? I have no idea when the lube was last changed.

magnetic plug? wow. , didnt know they had em

This is normal. It the wear of the synchros. I clean them with carb cleaner, then use high pressure air to blow the particles away.