After.
Fist I would accept the rig. Why buy and pay for something that maybe broken. They want your money that is the only reason they show up. You deserve to get what you pay for, not pay for a rig that needs work. As Marcus would say, Your money Your rules. I would be very cautious about due bills. Some rigs have been in the shop for months waiting on due bill work. They will do paying customers first, they already have your money...why should they hurry.
2008 Discovery 40X towing a Jeep Grand Cherokee