I just may be the luckiest guy...
 

my SE 13b that I bought last year has been laying dormant. Well I shined an overpowered flashlight up it's exhaust. viewing below the spark plug holes traveling to the exhaust port.. No chrome chipping. wait, it's smooth. like no chattering! Looked at the side housings. smooth and flat. I could not make out any reflections that would lead me to see excessive wear. Best part of all, this is the rear rotor! The front rotor looks better still. Time will tell if things are in as good as shape as I hope. My plan is to tear down in a month or two. I also have a 12a that need rebuilt. Story for later.

If the engine is in excellent shape why are you tearing it down?

Nice! Do rear rotors tend get beat up more that the front?

Rebuild because I am concerned with 34 year old soft seals. It also does not have compression. This might be from it being dry inside. I have not made a habit of rotating the engine. Just spinning for thin inspection and to try to hear the compression "phoots". I have no idea of the mileage. If there is nothing to be concerned with, I will clean the exterior and leave things intact.