The first three 5516s were produced without a leap-year indication and
link actually looked quite a bit different from each other. The earliest on the record (below, right) informs many design elements found on the early Royal Oak QPs; with a four-register layout, moon-phase at six, the month indication at twelve, and a sub-dial at three for the
link date. Pay
link particular notice to the lack of a leap-year indication, as this is the genesis of the layout we will see nearly 40 years later for the Royal Oak.