Depends... There are plenty of confirmed reports of people getting the iPhone 4s if you had a 4 or 3GS that is no longer made. I am not sure what they are currently sending now that the 4S only comes in 16GB.
I just filed a claim for an iPhone 4 32GB, phone was shipped today. Not sure what it is. Will know tomorrow. I have confirmed it is a phone coming directly from Apple, not an Asurion refurb. Worst case I get an Apple refurbished iPhone 4 32GB. Likely I will get a 4s 32GB... If i'm really lucky, i'll get an iPhone 5 32GB.