You are correct. There is a slate of candidates to be delegates to the National Convention signed, sealed and delivered.
The delegates to the State convention were elected April 9th. Application to be on the slate of candidates to the National convention had to be in by April 10th. That slate is full of GOPe stalwarts.
Those delegates to the State convention can only vote on April 30th for the Delegates to the National convention.
Lots of newbie Trump supporters flooded the April 9 meetings. But the need to apply by the next day was never announced to the attendees in my experience.
Lots of ways to dis-enfranchise the voters
So, Trump delegates have become voting delegates to the state convention, but you think that not many of them met the ballot deadline to go to the national convention?