I believe you literally egg out some holes, and you're good. It's so easy that you don't need, say, a YouTube video. Obviously, test-fit all this off the truck.
I would definitely do this if you have headers, since everything is hotter with headers.
The heat shield from the FJ40 manual steering box is easily modified to fit the minitruck PS box. But, of course, you have to still have an FJ40 heat shield in the first place... ;-)