QUOTE(Elbereth @ Apr 11 2008, 10:10 AM)

the copies are just backup in case something happens
worst that can happen to you is USCIS loses your file and you'll have to send everything again to your husband
Yes, the best practice of making two full copies of the submission is for reference. Copy one for the petitioner's file and copy two is sent to the beneficiary for reference and interview preparation. Many of the family related information and dates should be learned by the beneficiary.
If no copy, just fill it out again.