Sprite Seats - Packing Strip, wood

I was looking at the Moss catalog tonight and noticed that there is a wood 
"stick" (Packing Strip, wood) that is supposed to go under the seat rail. I 
never knew that there was supposed to be a stick there. Does anyone have 
the packing strip in their car? I'll bet not!

What's the purpose of the strip? I doubt it is to raise the seat.

Tim