It does matter in my opinion. While i currently drive an older Camaro and like the new one a lot based on what i have seen and read in various articles, I wouldn't buy a new one based on price alone.
And keep in mind in addition to the higher sticker price, Mustangs are discounted much more heavily than Camaros as well so the difference is even more in cash that you can keep in your pocket.
But my choice if I were buying today would be a Dodge Challenger anyway.