Yes it is, you've been approved. They just need to verify your mailing address..
It happened to me when I applied for this account back in August 2009..
That's kind of a hassle for them to ask for so much, you need to send them all three documents they are asking for? Unless you noted on your application that you make an extraodinary amount of $$ I don't see why they want so much backup. Do they not believe you? I applied with them 3 years ago and was approved as well but I was not asked to send any documentation. It makes sense that Citi would not ask you to provide these documents if they were not going to approve you but I would still be weary, in my opinion they are not loyal to their customers. I finally closed my AAdvantage account with them last month after being declined a CLI. I have never asked or been offered a CLI on that card since the day I opened the account and the day I ask for one they decline me despite the fact that I have always paid my bill on time, never late and have a 748 Fico. Good luck with them! I hope they are kinder to you than they were to me!