Is this a fan-rated box?

We’re trying to replace a heavy light fixture (from previous owners) in our bedroom with a ceiling fan. We can’t tell if it’s a fan-rated box though. Pictures from “our” side and the “attic” side here: https://drive.google.com/drive/folders/1hq9GrQqb3bhT74NZr16AgPaO0yNmGgg9