In most brewing cases, 'raw' grains are actually treated or cooked before use. Flaked and torrified grains are cases in point. One grain that is more likely to be used raw in brewing is wheat.
In all these cases, I find that employing the grain acidity curves in Bru'n Water to be relatively accurate. Barley malts and raw forms have similar acidity, while other non-barley grains including wheat, oats, and corn have less acidity. The supporter's version of Bru'n Water includes the non-barley curve that helps account for that lower acidity in those grains.