This is an older style IWC box. This doesn't really mean much. It is possible this watch came in this box from IWC, it is also possible the AD sold the watch in this box. The most important thing is that the warranty card is filled in correctly and that the case number on the card is the same as the number on the caseback. The watch looks good, it could use a new strap
Please note, it is very hard to judge the watches' authenticity by photo's on the internet. If you are unsure, maybe you can meet with the seller at an IWC AD?