How can I change the UV's on a font and then save it so that these changes are permanent?

I am working in a project that started somewhere in Unity 4 and worked its way up to 2018. 90% of the GUI in project was built using NGUI. The people in charge would like to keep using NGUI. I am having an issue where dynamic fonts will appear upside down when using NGUI labels in editor and builds. I have a hack fix that just swaps the top and bottom UV's for each character. Unfortunately this fix is temporary and unreliable. I would like to be able to swap the top and bottom UV's and save this out as a new font so that this issue will go away completely, but I am unsure how I can do that.

EDIT: This issue only happens with NGUI. UGUI renders the font properly so if anyone knows how to fix this without editing the font itself that would be fantastic as well.

Thanks in advance.