I would feel down there first. If you remove the lower seat cushion, you can also recover a lot of change, perhaps the build sheet, etc. Many people pushed the seat-belts below the seats. In the 1970's, I would drive with fools who ridiculed you for using a seat-belt. Wonder how many of those geniuses are still alive. Perhaps they thought they could bench-press 2000 lb in a 10g accident to keep their face off the windshield.