Can't recall ever seeing a cowl cover/insulation removed in one piece successfully. Would suggest that you make a pattern with craft paper, transfer to the fiberglass material, then attach a trash bag (cut open) to the fiberglass then cut it out and attach it to the car. At least that is what I've done.
Sorry don't have a picture of a firewall pad out of a car. Is there a specific area you need to do repairs on. Maybe we can offer shots of those areas to help. Ther were a couple of different suppliers so the look differs but that is likely not an issue except in attempting to copy those details in the final product.
NOTE: Moving this thread to the discussion area since this is less of a wanted (for a part) thread than a discussion thread