As to whether she would have helped, I dunno... that's pure conjecture. If that's the hypo folks need to go with so they can talk about the travesty of race relations in this country, I suppose that's fantastic.
Reading the report and assuming, for the sake of argument that it's true (police telling lies in police reports is not exactly uncommon), Gates was behaving in a completely unreasonable manner. Even if he did think he was being discriminated against, berating the officer who is only responding to a call is not the way to handle that.
This whole thing reminds me of an old Chris Rock Show bit about "How Not to Get Your Ass Kicked by the Police." NSFW
http://www.youtube.com/watch?v=uj0mtxXEGE8