Roman helmet decoration

[Ebusitanus]

Salve,
I was having a very nice debate with a frater of mine about decorated roman helmets and would like to prey the bright mind here a bit.
We find throughout roman helmet history those that were heavily decorated, those a bit decorated and those that were bare and "generic".

Say, per example, the Montefortino. Is there a chance that the nice decorations specially the first models show, are fabric based or could have been field modifications through the legion´s armourer.
I say this because I find that given the legionary custom to end up looking "smart" through better Gladius scabbards, pugiones, cingulum plates, etc, etc..Could the helmet have received this same treatment by the owning trooper? I´m not talking about punching a name in but rather the nice ring decorations around the brim. Would those field enhacements be fairly common? Would a hired armour fabrica do thousands of decorated helmets for newly raised legion?

Thanks in advance