Since you indicate your car is a deluxe interior car, ...the one thing I know for sure is that it would have then received the rubber trunk mat. As for extra insulation? ...the only thing I can think of is the jute padded insulation that goes behind the back seat. As for an 'asbestos' mat (actually paper backed tar-like, ...similar to/the same as that under the interior carpet) I do believe there was something in the forward area of the trunk (where the trunk floor goes up over the axle area), ... but not in the 'well of the trunk.
Undercoating was sprayed in the inside quarters (usually pretty rough/sloppy looking, ...but hey, that is how it was). I believe the spatter paint was sprayed over the undercoat, ...as for suppliers, ...I've usually found that what Rick's 1st gen carries is pretty good stuff.