The method of obtaining dyable versions of AF gear has been different each time.

In ARR you traded in crafted items for dyable versions that were patched in later (can't remember the patch).
In HW the AF set was originally from the first set capped tomestones, with the upgraded version being the dyable one.
In SB it was Eureka as mentioned.

Since there's no pattern, it's hard to say how it'll work in SHB.