Nothing good will come from getting the sword appraised. Why would you want anyone else to know about the sword, and it's potential rarity. Masamune should not even consider selling it. He was told by Shaon to give the sword to Toa specifically. And that the sword doesn't suit him. Did Masamune forget?
Wines contain complex and fragile flavor compounds. Once a bottle is opened, those flavor compounds start to die off. If you put a top back on it and refrigerated, it would maybe last a week. At no point, does anyone address this fact. Nor do they acknowledge that it's no longer a full bottle, since part of a glass was poured and drank. Is the merchant planning on selling this already opened, no longer full bottle? That would be stupid. And yet he never asked if Masamune had another unopened bottle to sell, nor how he would handle what is essentially a wasted bottle of wine. I hope the story doesn't pretend this is not an issue.