Quote from Arkayenroon live the itemID is always nil. its causing errors in blizzards own code because they use that to generate the chatlink.
you would hope they chose a better way to reference things than their position in a local list (which they seem to like doing a lot).
There is a concept of a currency ID, but there's no way to get that ID programmatically... and IDs for currencies you haven't seen will return nil results, even if the currency is valid (with the exception of the Archaeology currencies).
The itemID is actually one of 4 unknowns that are returned...
unk1, unk2, unk3, unk4 = 0 (usually), nil, 0, nil.
unk1 is 400000 for the new Raid/BG currencies, and 10 for the new cooking awards. Unk2-4 are not returning anything unique at the moment.
This behavior is the same across live, PTR and Beta.