Christies Late Roman helmet: 1 or 2?

[Nathan Ross]

How about the neck guard attachment: riveted or strapped?

Is that not a hinge at the back? Or would that be too crazy?

I'd like to see this/these proved genuine too - certainly among the nicer late helmets. Most of the more wayward fakes I've seen tend to look horrible, so on aesthetic grounds alone I'm inclined to give these the benefit of the doubt!