No, if you're looking for slugsmasher's coal hoppers, only enter in the asset kuid. As you have it, you're looking for a specific kuid, and with the filter of whitepass. He didn't make that kuid, so of course no results. Only search on the asset kuid. If you wanted whitepass's hoppers, you could search on author ID=whitepass, then look at all his content.
Norm