I think theres a distinction to be made between weathering and battle damage.
Weathering is the effects of environment on the armor. This would be dirt, grime, mud, subtle abrasion.. etc. The 'lived in' look.
Battle damage is the effects of battle on armor. This would be scuffing, scrapes, dents, bullet holes, and possible scorch marks. The 'I got attacked, and heres the evidence' look
I know theres a fine line between the two, but I think what Frizzle is saying here is that although there is obvious battle damage, the MC's armor looks relatively clean. My interpretation of those gray spots is that those are areas where the paint was worn away by use in battle.
Hope that solves some of the debate.
Looking good Alkaline.