The Oyster Perpetual is the successor to the Oyster.
The name comes from the fact that it has a perpetual function (self-winding).
At the time of its introduction, it was nicknamed "bubble back" because the case back was greatly swollen due to the addition of the automatic winding part.
After that, after improvements, it appeared with the same thickness as Oyster, and 1002 etc. became a representative part number.
You can check the inventory list of bubble bags from this dedicated page.
The Oyster Perpetual Date is an Oyster Perpetual with a date display.
1500 etc. is a typical product number for watches with a date.
These models have been repeatedly improved and are still being developed in modern times, and are treated as Rolex entry models.