BYU has made the tournament 3 times since then. They were dropped once by 2 seed lines and the other 2 times were seeded according to their true seed.
To look into it further, though, there's no way they would've been dropped for Sunday play in 2011, 2010, 2009, 2008, or 2007 as there were non- Sunday sites available to them to 1 seed line above them as well. However, it's possible they were dropped from an 11 to a 12 back in 2004 though can't say for sure without knowing the true seed lost. That means 7 of the last 8 times BYU made the NCAA tournament they were not dropped due to Sunday play. It is possible that it could happen and has happened before, but it is far from being a regular thing.