Help me order the right panel

[THISISWEIRD]

Hey guys, I've got some rust where the rear passener floor meets the bed. Just like where the hole is in the image attached (sorry, it's borrowed from someone here). I'm not sure what replacement panels I need to order. Can someone point me in the right direction?

 

[AZ79K5Project]

Here is where I bought a front floor pan. Navigate to the proper year. They have a pretty good blow up view of the parts:
http://www.rustrepair.com/repair_panels/onlinecat.htm?r=ru&p=sm