Modchipman.com Harddrives
 

Modchipman.com offers hard drives with an image of your xbox already on it so all you have to do it plug it in. Does anyone know if this is just when you get them to install it for you, or if it will be that way if I order one and have someone else put it in ? Please check it out www.modchipman.com and go to the xbox section. TIA

My guess is he would install the HDD for you.
Unless maybe you sent him a back up of your HDD and he formatted one with another XBox. If thats true, the HDD would be unlocked and you would have to lock it again if you wanted to play on XBox Live.