The list of names in the post's close notice is only the users who voted to close, not users who flagged. Close voting is a privilege that requires 3k rep on graduated sites.
Flagging a question to be closed when you don't have the close vote privilege only places the post in to the review queue so that users with the relevant privileges can vote to close.
If a question that you flagged is subsequently closed then your flag should be marked as "helpful", but that doesn't publicly show anywhere; only in your flag history. You can see your flag history by clicking the "x helpful flags" link in your profile. If your flag was not marked as you expect then read: Why does flag marking as helpful/declined not always correlate with moderator action? and What is a disputed flag?