I've seen NO indication or claim of revised units and it would really SUCK to order one only to have to send it back.
I have the second CS DD at home and with none of them i had problems with coil whine.
But i remember a user who sends his base back concerning coil whine and got it back "repaired".
I had this issue, and I can confirm that RMA done the job - new one is perfectly quiet and smooth.
Danny Lee did a preview and plans to do a video on the RMA: https://youtu.be/q8qE_-7X8yM?t=487