>>28615323
>1985 ford door armrest light cover
Where did you look that up? ebay?
Rockauto does actually show two types of dome light lenses for the vehicle, one of which fits in the actual dome light, and another that won't.

The one that won't fit the actual dome light is a Dorman part #74973, and it actually does look pretty close to the armrest light cover, but if you look closer you'll realize it's not the same. I thought at first it might have been the right part but you can see it's got a rectangular shape and the base of it is flat with a sort of pyramid shape to it. The actual armrest area lens doesn't lay flat like that.