Halo 1 National Championship T shirt question

I came into possession of a T shirt and making of Halo 1 game disc still in the plastic given out at the first ever Halo National Championship, in fact the person who owned it ranked very high, like in the top ten, but i dont know. My question is, how rare is this stuff? I’m not looking to sell it or anything and I am not expecting it to be worth a fortune to start with, I just want to know how rare of a piece I have for my Halo collection. I looked all over the internet and can’t find it and I am a little unsure it’s real, but most likely it is. Somebody help me.

Sent you a PM on this. Not sure if it went through or not, though.