MiloMorai pointed out that in 41, chermans alredee noo ssat flying below 100 feet hid them from Engerland's rader. The Horten was designed in 43-44 or so. The Northrop Grumman team didn't put a 109 or 190 on their radar test prop. So this'll probably keep the argument going for a while yet.
The truly cool thing, IMO, is NG saying the 229 could be used today with only minor changes.