Sound dampening/deadner?
 

I'm in the middle of pulling all useful parts from my 91 rs which is in my uncle junk yard. My 88 was gutted by the previous owner and now I'm trying to get all the rattles, clunks and noises out of it. I've already swapped over the interior but earlier I realized I didn't get the stuff that was under the carpet. Is that sounde dampener? I'm pretty sure it is but just wanna make sure. It'd probably make a pretty big difference I bet.