Did Roman cavalry wear face-masks in battle?

[Urselius]

It would have been considerably easier to form a human-shaped face mask out of bronze than out of iron. Given that the cavalry sports display was just that, a display, and the face masks were presumably primarily for visual effect, and at worst were only expected to protect against light, blunted javelins, then bronze would have been sufficient.

For a Roman armourer to go to the considerable labour to produce a face mask in iron suggests that it was intended to perform a serious protective function.