A little work, but builds up a foundation of skills which can be very useful in the future.
If I wanted an inside piece of a Youngstown door, I would make a quick mold of a door with either the craft store Michael's AMAZING PUTTY, an RTV type of product which makes good molds without mold boxes (easing the effort to make molds). If using this product, make sure the top of the mold (which will become the future "back" of the mold) is even and straight, as this will help keep castings straight afterwards. When the mold is cured, apply a good, even coating of petrolatum (Vaseline) to the cavity. Now add a new mix of putty, essentially making a door casting with RTV instead of resin. This "Mold-of-a-Mold" will make suitable inside parts of a Youngstown door with a coating of a small amount of JB Weld epoxy, the traditional type, available from Auto Parts Stores.
As a bonus, you also have a mold to make extra Youngstown doors. An alternative to the amazing Putty, is also found at an auto parts store. Buy a tube of high-temp 1200 degree exhaust gasket, such as made by Permatex. Build up thin coatings of this material with a flat sided toothpick several times until a casting of proper thickness is achieved.