I have this mule (Solomon Islands obverse) graded PF 68 from NGC. I see an occasional lofty starting bid for ungraded one on eBay, but only one sale ever. Exciting to have a rare coin, but possibly so rare no one knows or cares. Any ways to guess at a value? The non-mule variety is bullion only worth its weight. I watch eBay and have ChatGPT check from time to time.