this is the current application, revised this month; April 2013, as noted by "Rev 4/13" on the form. it is NOT the final version of the application though. the new law requires DESPP to amend applications to allow claiming possession of large capacity magazines on the same application as your certificate of possession. so a new version of the above app will be available sometime in the near future that will allow you to list on the same app the [hundreds of ] 30- and 100-rd mags you have for the AR you are trying to get a certificate of possession for.
I pray that the new version when it comes out has also removed the requirement of proof of purchase, as noted above in the first post.
also, there appears to be nothing requiring renewals of the certificate. once you have the certificate, it's final, it's yours for good.