looks like yellowjersey used to have decals, but they are out of the ones for the 5000 model.
http://www.yellowjersey.org/sekai.html

there's a 1975 sekai catalog there. it says the 5000 from that year is made from "Tange Professional 0.6x0.3 double butted Cr-moly throughout" and that it weighs in the low 4 pound range with the headset. that is an obscenely thin tubing diameter, and an obscenely light frame. with that in mind that it has received some dents is unsurprising.