A verbal Ok from gaming is sometimes given to the manufacturer, to go ahead and deliver the chips/strikes if they are produced late.
A verbal OK is actually written in an email.
Offical letters usually follow in a few days.

The normal process is gaming approves the notched chip or an actual strike before the goods are ever produced. Usually several weeks before production.
Manfacturers will very rarely run the goods before notched approval. If notched is turned down, they eat the lot.