Date code question

Let's think this over a bit. What's the first date on a portion of a car? What number is the only number that is cast into a portion of the car? Would it not be "cast" on the side of the engine block? Most times wont the block date be the earliest date on the car? Would a 70 model car have a 71 dated motor? A 70 model car could have a 69 cast date on the block and many do. All other numbers are stamped. That engine date was built into the block when the block was cast. It is the raised numeral so it was done during the casting of the engine block.
Small Block