Looking closer at the pics, I'm going to speculate - the PO didn't remove the retaining clips from the Becker. Those are the two metal things that stick down about 1/4 inch. In the OEM Becker they snap up unto the radio body. Your aftermarket radio doesn't have the same slots.

So....since the clips wouldn't retract, the ashtray frame doesn't fit right, so he didn't reinstall it correctly.

You need to remove your radio (hopefully it doesn't need any special tools to release any locks) then remove the OEM clips and look inside for the ashtray harness.

You'll need to source a few fine thread screws to remount the ashtray. I may be able to find out the size/thread count.