As HalfMetalJacket says, the idea was to take elements within the game's pool without having to rely on elements from foreign models. Regarding the chain mail, my intention was to refer to the loricas hamata of mild steel of the republican period (Celtic models) and I don't know if you remember it but in one occasion we already talked about chain mail (I referred to the one used in one of the models of your mod). But well; I recognize it, I haven't been careful enough in this occasion. But in my defense I will say that this is not a
Tercosketch 
.
Joking aside and as you say, it is plausible that the artist wants to reduce the number of polygons; it is known that a low polycount is favourable for good performance. We have been told that the armor sets vary between 8k-12k; but there are interesting ways to achieve this with little effort. Tell me John_M, how many k's does a complete set of armor add up to in this model?