That's a possibility, but considering where they a

That's a possibility, but considering where they are parked in relation to the 1st building I would say no. They seem to be parked at certain points around the 2nd build. I would think they would be closer to the 1st building if they held supplies for that building.  They look like the type with lifts in the rear that are good for lowering/lifting heavy items in/out of the truck. Perhaps the trucks are parked where they are picking up/or dropping off items for that build.

Could be wrong though.