It's up to you to decide if it's worth the risk. Getting everything back in a crate after you've inventoried it is kinda like putting toothpaste back into the tube.
You could leave it as they've shipped it and hope that everything is there and nothing was damaged in shipping. Van's does an excellent job packing and protecting, and I don't think I ever found anything missing when I did my inventories. But I would definitely keep it in an air conditioned space. You don't want daily temperature swings to create condensation.
Do NOT unpack everything and leave it in a dirty garage, storage space, or hangar. That's asking for trouble from moisture, dirt, insects, critters, etc.
You didn't say if your building space was ready or not, but I would opt for inventorying it into your air conditioned/heated work space sooner rather than later.