Yes but by both caucus and party rules, any of the delegates assigned to a candidate—via voting— who then drops out, become “free agents”. If the Paul folks, or anyone else, organize to get their folks elected delegates they can, once again, throw a wrench in the proceedings. Remember too that Iowa is a proportional delegate assignment state. Say Paul shocks everyone and comes in third on Monday night. Cruz and Trump continue to duke it out until the convention but Paul hangs around picking up a handful of proportional delegates and making sure he has plenty of convention delegates favorable to him that can vote for him either on the first ballot because they were assigned to a candidate that has dropped out, or on the second ballot when they’re free to pick whomever. It’s not a completely crazy scenario that leaves Rand Paul playing kingmaker.
https://www.iowagop.org/wp-content/uploads/2015/07/RPI-Bylaws-Updated-2015.pdf
...Delegates shall be bound to the candidates in direct proportion to the candidates’ respective vote shares in the Iowa Caucuses regardless of whether any such candidate has withdrawn from the race or otherwise does not have his or her name placed in nomination at the Republican National Convention...