I got my phone replaced at an apple store ... the replacements come in new white slim boxes (instead of the black ones)
I was concerned with refurb units - but keep in mind that the phone launched only 2 days ago.. so how would there be any refurbs available?
In addition to this, i checked the serial number of my replacement and learned that it is even newer than the original phone that i got (in regards to the production week) - and that it was also produced BEFORE September 21st... I checked this on the website that has been posted on other threads where a link was provided to check your phone's production week. Since it was made before September 21, it was made before launch day. Therefore, no phones that have been sent back since launch day would have parts that could possibly be in the phone I received... If that makes any sense
haha 
I was concerned with refurb units - but keep in mind that the phone launched only 2 days ago.. so how would there be any refurbs available?
In addition to this, i checked the serial number of my replacement and learned that it is even newer than the original phone that i got (in regards to the production week) - and that it was also produced BEFORE September 21st... I checked this on the website that has been posted on other threads where a link was provided to check your phone's production week. Since it was made before September 21, it was made before launch day. Therefore, no phones that have been sent back since launch day would have parts that could possibly be in the phone I received... If that makes any sense