I'd say that this keyboard is more desirable than ye olde Dell AT101 that you would compare it to. That one has also Alps switches, the same layout and similarly shaped case, but the Silicon Graphics (SGI) keyboard is more rare, was made by Silicon Graphics (demand by SGI collectors), has Cream Alps that are more liked and much nicer keycaps.
You could clean it up and retr0brite the Space Bar, then sell it for twice what the Dell AT101 or AT101W goes for.