Nope, there was no option for that material riveted to the lower cowl. In fact there are no pop rivets used on these trucks at all. Looks like an interesting modification done by someone after it left the factory. I wonder why they did that, but I'm the curious type. I also sort of wonder what is behind it. Hopefully it didn't trap any moisture and junk behind it and cause a problem. I've worked on so many cars where even the original body sealant used at the factory can sometimes cause more issues long term than they were designed to avoid. Sort of ironic.

Chad

 

My 1965 truck had nothing in the fenders like that. Just the stock steel inner fenders and everything inside the fender is wide open. Like Chad said, hope it didn't create an issue by holding moisture! I'm from the northeast originally, always hated to see stuff like that up there with the road salt in the winter. Odds are there would be a huge rotten hole behind that cover.
Your truck seems to be in pretty good shape so you may not have that to worry about!

 

Actually there is no rust in the fender Wells this must have been a southern truck all of its life. The only rust is an 8x8 square in the drivers pan and the left fwd cab mount. Everything else looks good. I've removed all of the added on material and looked..i just need to fill all the pin holes from the rivets that held it in place.

 

Hmm..yard art or scrap yard. Decisions decisions.

 

Last night I removed a majority of the big iron. In the pic below, the red line is the original center of the king pins. The holes pictured are 1/2 inch fwd of the original center line, i plan to use these for the CV alignment pins, so i think it will work out very well.

 

Moving along nicely..got a lot accomplished tonight. The pins are almost dead nuts on the lower frame holes. Just a bit wider so that will be on tomorrow night's agenda. Thank you every one for your input..this site is great...Mike