Whether he fancies himself as a Henry, CR7 or Van Persie... the issue with these comparisons with former wingers-cum-strikers is that those guys didn't just have great striking technique. It's that they were also seriously rapid. Gakpo, according to people who have watched him, is a fine striker of the ball and an intelligent player in the link-up, but he isn't particularly explosive.
The transition from winger to striker isn't as easy as people make it sound. If you don't possess some of the natural striker skills or instincts (back-to-goal & hold-up play, heading ability, movement in the box etc.) then your effectiveness will depend a lot on speed and endurance in order to lead the press, break offside traps and run at defenders.
I don't know to what extent Gakpo has the natural striker skills (I haven't seen enough of him) to make it at the top level, but from what I hear he's not particularly explosive. So that worries me a bit about these Henry or Van Persie analogies. He could well be another Depay or Sancho instead.