Old Celtic or proto-Celtic?

Someone sent me the following message. Should this properly be
called "proto-Celtic" or is Old Celtic or Common Celtic accurate?

>Old Celtic is more or less what linguists are currently calling
>"Common Celtic". In either case, it refers to the ancestor of all
>Celtic
>languages. It is similar to, but more archaic than, Gaulish. It is a
>reconstructed language, except in that it is possible that the
>oldest
>Gaulish inscriptions may date to the Old Celtic period.