Helmet, Belgian, Adrian, M-26/31 Passive Air Defense

[Frentebro]

Can anyone tell me how late these were issued & how to tell if they are post-WW2 refurbished.

They are painted gloss black & have the badge as shown in Marzetti 9.13.

A photo of the original liner & strap & any postwar liner that maye been installed would be appreciated.
Thanks!