I've been told that the NG can go much faster than 340/.82 but is limited to maintain the same type rating and commonality with the classics's. Here is an extract of a memo from my airline that would seem to back this theory a bit:
the overspeed warning or “clacker” is not in itself an exceedance but intended as an alert that one is impending. There is no requirement to make a tech. log entry unless IAS exceeds 360kt or IMN exceeds 0.84.