If offered admission to Tuck, your self-reported GMAT test scores will be verified. Tuck reserves the right to rescind an offer of admission should any misrepresentation or omission occur.
You don't have to submit OFFICIAL GMAT/TOEFL/Transcript during application. Adcom will request and verify those official documents after you take the offer. It is much better than requesting all applicants to submit all official documents.
Without official data in hands, I cannot tell you how many Chinese were admitted 2006 by region. What i can tell you is that total 8 T'08 Chinese from mainland are enrolled, two from beijing, three from shanghai and three from US right before Tuck. Personally I don't think adcom have geographic preference to China. Think about it with a big picture, China as a whole country.