Sorry for reviving this thread, but I finally found the post again where Lord of Mordor said that the Gundabad Orcs heavy armor upgrade MIGHT get the design of Bolg's forces from BOTFA movie. It is in German though, but roughly translated he basically says this:
Our plan was to give the Gundabad Orcs the design of Azog's Hunter orcs from the first Hobbit movie, and give the Dol Guldur Orcs the heavy armor [from the second and third Hobbit movie] (which we have implemented as you can see in the mod). The BOTFA movie, however, gives us a third option, which are the heavier armored orcs from Bolg's army. There is a possibility that the Gundabad Orcs [from the Misty Mountains] will get this armor as their heavy armor upgrade (on the condition that they won't look to similair to the Dol Guldur orcs), but that is something that we will decide upon during the development of the Misty Mountains faction.
Source:
https://modding-union.com/index.php/topic,30394.525.html (last post).
In any case we just have to wait untill the faction is being developed
.