Although the Mark VII isn't that old, I would find something sealed in a shipper as a bigger risk than a premium (coming from an individual person and not a business). There are frequently QC problems with this stuff, and with something with batteries especially, I'd much rather get something in good shape with the box and shipper but has been opened and inspected and the batteries removed. I'd only buy a sealed shipper second hand if it were a hell of a good price or if the seller takes returns.
Thanks for your help. I'll keep that in mind