Yeah they started phasing out the 'S' bolts in 77 according to that doc. Must of still had loads left a few years later though as i recall some of the original bolts on my 1980 TS185 has the S on them. Might be good bolts for a concourse resto but for a race bike or bike that sees tools often i would look for newer higher quality bolts. Suzuki bolts tended to be soft and usually had undersize heads that do not fit well with appropriate spanners/sockets. Eg for a 12mm hex, it might actually measure 11.60mm. If they are old bolts you are tiding up with a file/belt sander, to get re-plated the hexes may even end up even smaller.