Short answer: Yes.
The manner by which Bids are extended depends on a few things. Most of all, it depends on the way your recruitment is structured. Often times, an informal process relies on a Single Stage Recruitment. This means students are initially categorized as Potential New Members (PNM's), and can be invited directly from that stage to "Sign" to their chapter.
In other cases, there are Multiple Stages in the Recruitment Process, where students receive invitations to "Preference" events. These are structured a lot like mini-interviews, and is often the final stage before receiving a "Bid".
As an officer using GreekRush, you'll always know what Student's stage is and whether or not you can invite them to the next one. This information is viewable from the myRecruitment tab, under "Potential Recruits".