I just checked TV.com's TPIR page, and I discovered they have episodes lined up (along with their corresponding recording dates) up to and including April 1. So with that taken into consideration, I have a gut feeling the February 15 episode may end up airing on April 4. But until CBS formally makes the announcement, I would take April 4 with a grain of salt for now.
And btw, April 4, when it last fell on a Monday (in 2005), the episode was pre-empted due to the Procession of the late Pope John Paul II coverage. If a make-good airs on April 4 this time around, I can see it as being "payback" (in a (make-)good way) for what happened the last time April 4 aired on a Monday (and the April 4, 2005 episode did not air on the East Coast on the scheduled air date, and aired all but the first 15 minutes of it on the August rebroadcast date - talk about a double Whammy).