66 Galaxie Firewall/Cowl Panel Insulation Repair/Replacement.

So here is the old firewall or cowl panel insulation from my 66 Custom 500. It’s broken in several places and a piece or two might be missing. Have the guys that have had this out encountered this problem? Should I try to fix it ??? And reuse it or do the adhesive mass panels and insulation materials available aftermarket good enough to do the job? I counted 8 retaining pin holes on the insulation that look like they go through the insulation and lock into the firewall. I could probably find small plastic plugs to fill the holes in the firewall. There are so many there already!