1970 C10 Cab inner cowl restoration, HELP!

[Auroch]

Hey Guys, this is my first post on here, hopefully you can help.

We're in the middle of restoring a 1970 c10 cab, and everything was going smooth until we took the lower cowl off and revealed what you see in the pictures... do you know where I can buy repair panels for this area? I haven't been able to find any. Any other tips on what the best method is to attack this? I've heard people removing that side vent (not sure what it's called, the "ear" looking thing) completely and patching it.