Yes I saw that, it's also missing the L24, however 903 Blue is very rare for HS30s, especially early 70 models and it's of course quite a low VIN #, so a well worthy project IMHO..
$20k is up there for a car in this condition, but if you consider what good cars have been selling for in North America (and they are HLS30's made in a lot more volume) I don't think it's unreasonable.