Here's the latest ... Jegs.com sent me an email confirmation, with a new date:
Please note that part# 257-63285 is currently out of stock at JEGS. So that we may better serve you, we have arranged to have your part shipped direct to you from our vendor. Our vendor has provided an estimated shipping date of 04/5/2012.
So, if you're interested in the Coker wide whitewalls, you'll have to be patient. The 4/5 date seems to correspond to the 3/30 production date that kartgreen mentioned. I can live with that as long as April doesn't become August.