I have no idea if this is official or just something we created ourselves, but I've uploaded the frisbee CAD I found in our 2013 robot here:
https://goo.gl/e4MCL7
I put in both the solidworks part and the STEP file, but let me know if that doesn't work for you and I'll try something else.
EDIT: I'm pretty sure it's not official, but I'm not sure how accurate it is (I wasn't on our team in 2013 so I'm not sure if it was created just for appearance or it matches the actual parts). There are some other models here that are probably more accurate:
http://www.chiefdelphi.com/forums/sh...d.php?t=110515
This site has the 2013 field and KOP but I can't seem to find a frisbee in there either, unfortunately.
http://www.catalogds.com/db/service?d=first&c=browse