Wrong sight in the right box - HiViz LITEWAVE Illuminated Rear Sight, Interchangeable

I received the sight for Christmas along with my Father-in-law. We had both seen a Performance Center Shield at the local Academy with the HiViz sights, and were really impressed with the difference. As we are going about removing the original rear sight and prepping the new sight to be installed I noticed that the set screw and sight base was different. Confused, I compared the rear sight that I had gotten with the one my FiL received. No doubt it was a different sight but the packaging was all the same. I'm currently in the RMA process and will update when the new rear sight is received. Probably just some factory error that many wouldn't catch. My FiL loves his sights so far, I'm just anxious to get mine.