Having been there when Mark receives incoming products. I can offer the following tidbit of information.
When Mark gets a shipment we are talking 8-10 5 foot boxes stuffed to the gills with AEG's. His initial steps are to verify the packing slips with the actual product boxes. As he checks them off he can actually name who they are where they will be shipped to. The ones that have been pre-sold then get packed up and sent either that day (time permitting), or the following day. Mark is always giddy when he does this cause he knows how much we airsofters look forward to getting our "toys".