NY Divorce: do I need index number BEFORE getting spouse to sign/notarize defendant affidavit?

I would like to consolidate my visits to the NYC clerk office - is it acceptable for me to bring a signed/notarized defendant affidavit (form UD-7) to the court along with the summons and other paperwork and then get an index number/open the case at that time? ie, the date on the UD-7 would precede the date on the UD-1. Or do I have to go to court to get the index number on UD-1 first, THEN get the UD-7 notarized, etc? Thanks