On this picture, as you said Domitius Ahenobarbus' sarcophagus, we can clearly see the representation of a Lorica Hamata.
As i have been able to see it in real, and compare with other representation of a chain mail, i can put forward that this frieze represent a chainmail too.
If i remember correctly, i believe that Polybus give us a description of the equipment of a legionary (Hastati / Principes /Triarii), with their distinction of ranks, weapons and armor. Probably he spoke about the Lorica Hamata as a part of the equipment of one of the three type of legionary during his time.
I haven't made that much research, but the Lorica Hamata do exist, we can speak about its broadcast if you want, but not about its existence in my opinion.