Along with the title and bill of sale, they will want a weight if not in the computer.
The other thing is they will charge you tax, this will come off there computer and is probably WAY off. Make sure to bring a blue book (of any type) print off to prove it's worth less than 3K. If less than 3K they must charge you on what you paid for the rig. If they say it's worth 3K or more, they charge you on "car value" in there system. This means if you pay $500 for a rig and they say it's worth $3200, you pay tax on $3200.