That's the way VW Type IIs came, to include the single-and double-cab pickups.
The belly-pan was 'optional', used mainly for structural reinforcement on the open-top models. I believe some models shipped with the left and right sections but no center section. The forward 1/3 was covered by a removable pan under the cab floor.
Running boards were an aftermarket item.
http://www.thesamba.com/vw/forum/album_page.php?pic_id=229886