We had a similar aged Corona in the late '80s and that thing was like 90% rust. It even had some a steel plate riveted under the windscreen to hold the windscreen wiper because the windscreen wiper mount literally rusted off.

It's phenomenal how much improvement there was in rustproofing between even '70 and '90. If a '90-'00 car hasn't been crashed and not driven in very salty conditions, you can find them with essentially no rust even now.