Systems of subjection of the montefortino helmet

[marcii ulpi messala]

I have observed which in the helmets montefortino there are two systems to fix the strap that comes from the fin later of the nape of the neck to barbuquejo, these are two to per to us with conical head; one with two pins of fixation that leaves below the edge buccolae, and another one with a single pin of fixation that leaves the outer face of buccolae, means this that a system is previous in the time to the other and therefore it belongs to a more primitive model?