"A bar of gold made by a recognized bar manufacturer regardless of shape and SIZE and upon which is reported the exact weight and purity of the gold as well as a registration number." (my italics)
The larger bars are called ingots and are made by casting. That is poring molten gold into moulds. The smaller bars are made by pressing gold strips with a huge multi tonne stamp much in the same way gold coins are made. These are usually called biscuits, although not so crunchy.
The point is, ALL bars of gold, regardless of size, should have stamped on them, the weight, the size and the manufacturer's stamp.
