lead in the bashplate, or under the engine will get around any minimum, but heavy materials or steel instead of ally, doubt it.
If they are serious about this rule, and the enforcement of such, a random test would have been done this year, afaik its never been random.
it is too easy to circumvent.
At the first round in france in 2012 it was "broadcast" that the weighing would be done at scrutineering which it was, for all we know bous tyres were filled with water.