I would think that you are correct - Swartz and Lincoln are probably below the 5% threshold for reporting, thus the omission. Why are others who hold less than 5% listed, you ask? Because, as officers/management of the company, such reporting is required regardless of the size of their holdings.
5% of 391M OS (the old number) = ~ 20M. S&L could still be holding a big bunch (darn it). But my WAG is that they/he holds something around 10M or less at this point.
JMHOs,
SGE