Can you help me identify this disc?

I bought this disc off ebay a couple of days ago. ive thrown it a couple of times and it seems pretty stable . The bottom has a very shallow rim with a bead that kinda feels like a roc. The flight plate on top is completely flat. Its a lower grade plastic like dx or pro d. This disc is stamped with river city flyers team challenge from sept. 25th 2004. Anybody attend this tourny or know what this disc could be?

[Discman00]

does it say innova any where on the underside?

 

[Allonzy]

Also, I just want to add that if it was an Innova disc it would probably say Innova on it, and failing that I am positive they wouldn't custom stamp the Gateway logo on anything. For the most part, DG companies don't play nice with each other.