On the interior bottom edge of each door is a strip of metal about an inch wide and is held in place with eight small sheet metal screws. There was nothing they were holding in place, so I was thinking there's probably another weather strip that goes there. At the following link, is a picture of a door with a lower weather strip that's held in place by a metal strip. Can't tell if it's the regular door weatherstripping or something different.

http://www.jimcartertruckparts.com/Articles/Advance-Design-Door-Weather-Seal.php ,