Yes, Robert's threads are what have "inspired" me to rethink my intended process. And Robert, yes, the truck has the flip out vent (1949) and the patch panel (1948) has the flip out vent as well. The vent frame on the original panel was kinked enough to render it unusable (at least with having a suitable replacement on hand).
I have some body hammers, a few dollies, some scrap pipe, a vise, and an anvil.
Why do I get the feeling I will be building this piece myself from some "old metal" from the old cab.