Check out the previous posts in this thread. On Feb 10 XWB posted a picture by Romain (F-WWDW) and on May 04 ca350 posted another picture from the other side (F-WZDW). Let's wait 'till it flies, then we will know what it is supposed to be (IF Airbus corrects by then).
Normally, the registration from the transponder (which we saw on FR24) is correct even though the sticker on the fuselage is wrong. I believe this is the case this time too. But yeah like what peter said, let's wait for more pictures when MSN 172 is out in the open.