I think it does rule out any NOBUS vulnerability with these curves, doesn't it? My thinking may be a bit sloppy here, but for a curve to be NOBUS exploitable with N-bit security by its creators, I think it would have to have a property only shared by 1/(2^N) curves. It would be impractical to hash 2^(N-1) timestamps until you find one with the desired property, for any decent size of N--which is how many you'd have to do on average before finding one with that property.