Hi, I've got the same guitar in metallic blue, same uncovered trussrod, 21 frets. The bridge is a chrome khaler flyer, the tremolo arm is full metal without plastic part and there is the same kahler locking nut. It mounts SSS instead of SSH but the body is carved for SSH configuration. The body is made of a sort of plywood. I bought this guitar in 1989 but the year of production seems to be 85 or 86. As you can see here http://www.epiphonewiki.org/index/S-Series.php these guitars seems to be something between the 400 and the 500.
