IMHO yes the lower ones look to be originals. Don't have a 70 Assembly manual for suspension but believe that they would have been heat treated (dark steel though not phosphated.
Can't recall if they are also safety red ( a die) over the finish, in 70 but sure Ed will be along here any time to give his reflections on the piece. Will leave the other nut question open for him also at this point :0
What you purchased looks like hardware store nuts and bolts IMHO