Is it permissible to trade currency without weighing when the amounts of both counter-values are known?

Primary text

It is permissible for two parties in a transaction to trade without weighing if they both know the exact measure of the counter-values. Similarly, if one party informs the other of the weight of what they possess, and the other party confirms this, the transaction is valid. This applies specifically to exchanging a Dinar for a Dinar.