Evidence for legionary vs auxiliary helmet patterns

[Peroni]

The general form would be the same as the helmets being produced anywhere during that time, but the specific details would be unique to the craftsmen. Is that reasonable?

That's exactly what I meant David. The Gallic 'I' finds demonstrate this very well. Differing shaped bowls and eyebrow excecution, but all have the same basic fittings not seen on other contemporary iron helmets, such as soldered-on crest finials, tubes for pinnae gemina, rear slide-in plate for crest attachment and are all copper alloy.

Similarly, a variety of helmets from the late first - early second century from the Brigetio area show similarities in style such as highly angled brow guards and eyebrows, not just on iron helmets but copper alloy as well. This shows a possible regional trend at the time or speculatively, that the brow guards were raked at a higher angle to combat the use of the falx(?)

Auxiliary B II at Cardiff (all copper)
Auxiliary B III (brass with iron cheek guards and crest finial - private collection)
Gallic J at Caerleon (Iron)
Gallic J at Vienna (iron with cross-bracing)

Another helmet that could well fall into this category is the Theilenhofen cross-braced helmet (iron - from an auxiliary base)