I will be honest, I do not know too much about the 12A. However, seeing that a lot of the parts for them are not easily available at this point, I would assume that there is a demand for the engine parts depending on the condition. also, you need to factor in variables like initial engine cost, time invested into tearing it apart, cleaning, speccing parts to see if they are usable, etc.
It all depends on if you are just trying to make a quick buck, or if you are wanting to help out the rotary comunity.
If your answer is easy money, look elsewhere buddy!