Moodle SCORM completion status/scores are stored in the scorm_scoes_track table - there are several records for each SCORM sco/scoe. The SCORM package needs to report the completion and scores for the data to appear in Moodle. I have always assumed that if the SCORM reported a score - it was automatically stored in the gradebook but you may need to check your grading settings for the SCORMs you want to track.
Hope that helps.