The one that fell off was "cylindrical". Had the same shape as the muffler, cut in two halves.
Didn't think on taking a picture before throwing it away.
Basically the lower part fell off and only stayed hanging by one corner. When I started pulling it, the top part came with it.
The top part had some sort of insulation that looked like a white rag or cloth.
Maybe I misunderstood you then. You said muffler but that it was cylindrical and I took that to mean it went around the whole thing, which the muffler heatshield does not do but the cat heatshield does.
Either way you don't need it.
Yeah, I think you're right.
My muffler is rusted thru since the day I bought the truck, never replaced it because I kind of like the rumble the V8 makes, but now is falling apart, sooo..... there goes another $140....