I am definitely of the opinion that NFOW rainbows are virtually all wild. The point of my earlier post on this topic was that the NFOW is chock full of rainbows and the MDNR isn't stocking them, so they pretty much have to be wild.
Since the early 90's, I have probably spent 20-30 days on the NFOW and over that time, I probably have caught 9 raindows for every brown and that is for the entire length from Kelly Ford/Rainbow Spring down to the last riffle above Dawt. I will say that the last time I fished the river was 2006, so there may be a higher proportion of browns now, but that was my experience when I was fishing it a lot.