DIN hole/frame question for 1987 911 Carrera

[DriftingCloud]

I recently bought a 1987 911 Carrera where the PO(s) removed the factory radio, cut the wiring harness, installed an aftermarket radio, pulled the aftermarket radio and DIN frame, and finally installed a radio delete panel that won't stay in place.

I want to reinstall an OEM radio that I have, but something is really fishy about the dash metal behind the plastic face. I have an OEM DIN frame, but it's like it doesn't fit. The bottom is the only edge where the frame seats. the sides seem too wide, and there's nothing to catch on at the top.

Does anyone have pictures of what the edges of their metal dash (behind the plastic face) look like? I'm really confused about why an OEM DIN frame seems like the wrong size.

Here's what my empty radio hole looks like. Any help, especially images, would be greatly appreciated.

[DriftingCloud]

What's gotten me really suspicious is this picture I found. It clearly has more metal showing on the sides and top than mine does. With metal edges like this, it would be easy to mount the DIN frame.