Hi LMD, and welcome.

Just so you do not waste your time here, you won't get anything close to 1.5BTC for a Cas error here on the forum.

Multiple just sold this last month via Stacks at the $88.5k mark, and all were graded. On April 3rd, date of auction, BTC was right around $83K-$83.5K, so premium on a graded Cas error was around $5k, or 1.06ishBTC sale price. Even the grading did not impact sale price between the MS61-MS65 range. Being yours is raw, you can likely expect less premium that a graded Cas.

https://auctions.stacksbowers.com/lots/view/3-1HB4LC/2011-casascius-1-bitcoin-loaded-firstbits-13lv9h3k-series-1-casacius-error-brass-ms-65-pcgs
https://auctions.stacksbowers.com/lots/view/3-1HB4LP/2011-casascius-1-bitcoin-loaded-firstbits-188jttuv-series-1-casacius-error-brass-ms-62-anacs
https://auctions.stacksbowers.com/lots/view/3-1HB4M0/2011-casascius-1-bitcoin-loaded-firstbits-15kgxa59-series-1-casacius-error-brass-ms-61-pcgs

Just setting realistic expectations for you. The forum is more of a wholesale marketplace. If you are expecting high premiums I would consider an auction house in the future.
GLWS.