I was going to say "If you have all the Offical Downloads, including the Endangered Species Animals, then you have CC" but then I got to thinking that it may not be quite that simple, as you say you have installed CC at one time, but due to a missing disc problem you want to know if you are still "running on" CC. It is my understanding/experiance that the "main thing" (best thing! ) that makes CC different from "running on" ZT+DD+MM (aside, of coarse from including all* the Offical Downloads) is the inclusion of the dlupdates folder.
With CC, the new dlupdates folder is read before the other folders, which makes it an easier (less-conflicted) place to stash (most) the User Made dohickys that you want to add to your game.If you are playing strait ZT+DD+MM (or ZT, ZT+DD or ZT+MM) then your only choice is to put (most) User Made things in the Updates folder. In some instances, this was causeing conflicts with Offical stuff, which I suspect was why BlueFang added the dlupdates folder to CC in the first place! (I say "most", as some User stuff has a different folder-placement requirement, but 99% of the time, it's ethier the dlupdates or Updates one.)
So my advise would be to:
Find your Zoo Tycoon folder (with Windows Explorer), and look to see if you have a folder called dlupdates.If not, then you are not "running on" CC.
If yes (and you should, since you say you did install CC at one time) then take a peek inside it. If there are things in it, do they show up when you play the game?
If not, then- again- you are not "running on" a true CC.
If the dlupdates folder is empty (and it comes that way- you have to fill it yourself) then the easiest thing to do is download a User Made Animal/Scenary (avoid Buildings at first, so you don't have to fool with DLL files) and put the ZTD in the dlupdate folder.
Boot up your game, open up a Freeform Map and check to see if the Animal/Object is available.
If yes, then you can classify yourself as truely "running on" CC!
If no, then you know that your game can't read the dlupdates folder, so you don't "really" have CC, and will just need to remember to put any User Things you download into your Updates folder.
-ZW
P.S. While you could move an Offical ZTD Animal/Object file from one of your other folders into the dlupdates to check it, remember that unless you have a Freeform Unlock, many Offical Animals/Objects will not show up at the start of a Freeform Map. Useing a Senario Map isn't a sure thing ethier, as offten certain things are coded "off limits" during certain Serarios. User Made stuff doesn't have this problem, (at least, not in Freeform) which is why I recomended a User thing to test your dluptades folder.
* Don't ask me why, but the Sable Antelope was not included with CC. You have to download it seperately.