[K03NT3S31N]

That would be a lot of effort sealed boxing a whole new iPhone to have the exact same product but just not a potential blacklist.
Unless there was another method you were hinting at that I'm missing?

What I meant is go to a local store and buy the same phone model legitimately.
When you're home you only swap the Phone for the one that you EB'ed.

Go back to your local store and return the product (make up an excuse).
On the first glance they can't see if it's the right phone, only when they power it up and compare IMEI / SN with the one on the box.