yes it is
doorknobs can be made out of metal, gold, or copper
Car door panels may be made of a number of different materials. Most of these panels are made from metal or plastics.
The same material as your car or mine.
Steel
Metal lol
We can take the style from movie as they take a thin part of material put in the car door from outside and try to move it hock.
Polypropylene
It will be made of many components the casing material will not matter much.
There should be a paper label attached to the door-jam on the driver's side door.
A car chassis is made of heavy boxed steel, stamped steel or aluminum.
Safety glass, same as your car or mine.