These feet are not exactly the same as the original Atari 2600 feet, but they are as close as it is possible to get.
The originals were a straight sided, stamped out circular disk.
These replacement feet are the same base diameter, but the top diameter is very slightly smaller giving them a slight taper making them appear a little smaller. They are also not quite as tall (but less than a mm shorter), which means that you would need to change all four feet to prevent any rocking of the joystick in use.
Once fitted they look virtually identical to the originals.