So, 1.14 basically redid every graphic for every block/item -- don't get me wrong, the mod is a great utility mod, but I've played this mod since 1.2.5, I think it's time the graphics caught up with the times, from a graphical standpoint.
I wanted to try and update the textures to better represent the current state of the textures of the blocks/materials these chests are based off:

https://i.imgur.com/RXPFOhN.png

I'm willing to upload these for use in the mod, if you're interested in using them, but if not, that's cool too.

3 months and no answer... yikes. Well...
You could upload them as a resource pack on CurseForge! Please do that, at least I would love to use it. Other people would too, I bet.
Edit: Welp, I've made my own lol.