If they can show visuals that are comparable, I don't see what the motivation is for this. Not saying they will or should lie, but why emphasize points of comparison that can be viewed as a deficit when it's likely it will make little difference in the end product to the vast majority of your audience?
MS will have the most success by showing they can go relatively toe-to-toe on visuals and maintain and exceed the services advantage they have held. Calling out teraflops does nothing for them (and I'd argue it does little for Sony as well).
I personally think that you shouldn't announce specs at an unveiling of a console where the general media are invited. 90% of them won't care because they don't understand it. Case in point, when Cerny announced the 8GB of GDDR5 RAM, no one in the audience batted an eyelid.