Where the belief came from, that Apulo-Corinthian helmets had cheek pieces?

[Corvus]

I think the overall consensus here is, that the Apulo-Corinthian helmet type never had cheek guards. Especially because every helmet found didn't had one.
So why are so many illustrations, if not the most (for example in Osprey books) depicting this helmet with cheek pieces? Are there any ancient  frescos or reliefs that do that as well?

It doesnt make