It depends on what the "contingency" is. If it is based on something beyond your control, such as the results of a background check, you do not have to report it yet, since it may not materialize. But if the "contingency" is under your control, such as you (for example) being available to work by a certain date or relocating to a certain location, then since you determine whether and when the contingency is fulfilled, the job is essentially guaranteed to you if you want it--you, as stated, control the event necessary to qualify for it. So this type of "contingency" is not really a contingency and would be treated as a final, non-contingent offer.