Steve, I suppose you could be correct, but the way some of the GM docs are presented just makes me think otherwise like there is something more to the Z87 than the cowl seals and the underhood insulation. Case in point is this from the GM Heritage Center docs for the 1970 Camaro: https://www.gmheritagecenter.com/do...rmation-kits/Camaro/1970-Chevrolet-Camaro.pdf at the bottom of page 7 it lists the optional components for the RPOZ87 and it specifically line items the cowl seals, the underhood insulation and the "additional body insulation": Seems a bit strange to me that they would line item this way if the "additional insulation" was the hood insulation and cowl seal combinations. See what i mean? Another interesting statement is on page 16: which is exactly what the OP was asking about. i think the "underbody at desiganted areas" is maybe the trans tunnel and mine has some on the lower firewall also. I do not know if my car was dealer undercoated. Maybe a good question for the original owner, but she most likely won't remember.