A 12 point anything will never have the "grab", or the shoulder grip of a proper 8 point socket, which is purpose designed for a square head bolt. Lots of metric stuff "sorta fits" other applications, but with 80 years of wear, exposure, and corrosion, why chance it for a few bucks to get the right socket? Save yoursrlf some grief, and get the right tool for the job, which is an 8 point socket for a square head bolt.
Be a hero and lend it to your friends after they strip their bolts.