No, and I admit that it might very well be wrong. I read this on Slashdot and reddit (I can find some specific comments if you'd like), which obviously are not very reliable sources. But the articles I've read haven't mentioned when he died at all (unless I've somehow missed it), which obviously generates rumours.
Edit: According to harshpotatoes I am wrong, so please disregard this.
For what it's worth, last night -- before and after the presidential address -- on the bottom of a bunch of TV channels (ESPN for one) the reports were that the operation was carried out last week, not yesterday afternoon. You may have been wrong, but you certainly aren't crazy. :)