The good news: The boys are staying at my dad's tonight so hubby and I can build the bunk beds.
The bad news: One of the boxes is missing the hardware, and I called the number on the instruction manual and they are open Monday through Friday.
This doesn't work out so bad, because we can build the bottom bunk and add the top bunk later. We need to see if they also have the guardrails, since they were no longer in stock when we bought the bunks. This forces him to sleep on the bottom for a while (and get used to a Big Boy Bed), and he'll still be happy because he'll be in his new bed.