Door Panel Questions (for my '63)

[TimC63]

I'm disassembling a couple of doors before I have them sandblasted and had a few questions.

1. What type of screw head or what type of driver do I need to remove these screws (I've never seen these before)?

2. What type of weather-stripping is this and where can I buy? It seems as if it were once a pliable clay material that dries and conforms to a foam like material once installed (just a guess).

3. What trucks came with what mirrors? I want to use the mirrors that are mounted with three screws in the embedded door nuts which I believe came on light duty trucks, but the passenger door I picked up doesn't seem to have the three embedded provisions (I'm assuming the passenger door was off something heavy duty, wide load, etc).

Any help would be appreciated and thanks in advance.