Yes, the code itself is correct but the icon files got switched somehow. The find next icon is incorrectly set to the up arrow and the find previous icon has been set to the down arrow.
You can see this here:
https://github.com/Sigil-Ebook/PageE...-next_16px.png
https://github.com/Sigil-Ebook/PageE...vious_16px.png
I will rename both files back to what they should be for the next release.
Edit: The files were switched back, so the links above should now show properly