I'm not sure how many were made. I just know where I was told it came from. I know these were given out at the US Toy Fair too, as I've seen the review done on the Michelangelo toy. There's a Donatello #245 on ebay right now too from someone else.
Here's the link to the toy fair I was told these were from. I know I searched for more information and wasn't able to find it. I do know that they are official and are a part of that set though...
http://www.hktdc.com/fair/hktoyfair-...ames-Fair.html
It's really cool you had the Donatello, why did you sell?
Personally if this was not donated to be sold I would not be selling - I don't have this set myself yet.