While Trump, may, in the interest of the "art of the deal" sell us out on things like bump stocks or suppressors (likely with a "big picture" nod from the NRA), I don't for a second believe he would sell us out on things like "gun and ammo licensing".
IMO, likely from a lack of understanding, he looks at things like bump stocks and suppressors as "accessories" and doesn't look at them at a second amendment issue. The same as many, many gun owners who don't know or care about them. I think he knows what would happen to him politically if he sided in favor of restricting firearms themselves.