I just started a game to check some things out.
I had jump so I decided to see if the back crates in The Stable (Harmondle) wagons could be opened
Hit jump but went too high and.......
ended on ledge at the top of the stable.
Where there was an extra crate that has some junk but two more horseshoes.
Learn something new...........

I can confirm what you say. Indeed the chest contains the aforementioned horseshoes. You can also get to the ledge by flying and entering the opening on the second story.

What it also made me realize is that Wizard Eye does not show chests as 'points of interest' when outdoors. I guess that I never really noticed their absence before. My GM Air mage did not show any chests out doors when they cast WE but they would show up when indoors.

Learn something new every day, or try.

You can access that chest from the ground. Just look up and click on it.

Discovered a neat little trick while running around The Maze in Nighon. Minotour Lords will get stuck in two doorways. The secret area off the entrance hall and the small secret room with the chest in it. Get them to follow you into the first area. Run around to the back of the small room in the second area. They get stuck every time and you can beat the hell out of them.