Does anyone know if there is a way to upgrade old Legendary Gem of Many Facets?

[Sarlona Raiding]

I noticed the new ones I craft have a green and yellow augment slot instead of just yellow. I would love to add that green slot to some of my old gems.

 

[Aelastiar]

Reroll

 

[Bjond]

I noticed the new ones I craft have a green and yellow augment slot instead of just yellow. I would love to add that green slot to some of my old gems.

IIRC, the extremely old ones are stuck as-is (I have a few of those).

Wiki has the modern epic+heroic with one yellow and legendary with yellow+green. You should be able to check the base result of an epic upgrade or legendary reroll without actually spending mats (pop it in and see what is displayed).