NRA probably won't pick up a lot of new members anyways, unless they seriously address their marketing to all the millennials getting into shooting. They had a good run of Obama panic to drive them, but now they will need to do it on their own merits.
I could see them being concerned this will steal the thunder from them pushing for national reciprocity... which is the one I don't see passing.
I doubt they will push hard for it and my guess is they will sit on the sidelines, but they'd better not actively try and sabotage it or they will have a lot of p-o'd members.
IDK about getting many millenials involved. Our nephew is one, and I can think of only one of his friends who is into shooting at all.....
If it doesn't involved dabbing or Irritating Orange, they just don't care.