Treasure Keys for Galleons Graveyard

How do you get the 4 treasure keys for the dungeon, if at all? I've searched and the most recent thing I could find is from two years ago with someone stating it isn't possible, but is it possible now? Also all the things that show up when I search it up reagard the dungeon keys, which to clarify, isn't what I'm looking for. I am aware it isn't required but I still want to know. The wiki says a bit about it in the Graveyard Galleons wiki, but it doesn't state anything on how to obtain the keys, nor have I seen the dialogue it's referring to, so I'm assuming it's outdated? I've also looked around each dungeon rooms and outside the dungeon but found nothing.

TL;DR I've tried to search it. Tried to do my own research. Could not find it. Is it possible to get the treasure keys, and if so, how? (Trying to be thorough to ensure as little confusion as possible. Sorry if this is a common question or posted recently idk how to use the forum search effectively.)