Always... they were sitting at the front of the car :S I thought he put them there until I get under and find the jack with about 1mm of the diff sitting on it bowing out to the side. LUCKILY i always go body first and head last or I would be dead O_o wow I never realized how close to dieing I have come in my short life.
Safety first no matter how much of a rush you are in! always double check other peopels work aswell! Not because you dont trust them, but you dont trust them.

Anyway back on topic like I said your best off asking the supplier if it was a genuine mistake, however check the part numbers and things before asking so you have some ammo. And always be nice about it, nobody wants to help an asshole.