Brief backstory on this screenshot:

One of the Empire's pioneers decided to wander a little too close to my territory for my liking.  I waited until they established a city and declared war, attacking them on the next turn.  I easily took the city, which had no defense, and noticed they were already building archivists.  Rather than mess with it, I allowed it to be built.  It was built using the Empires model. 

Now that I've built other buildings in town, which appear to be in the Kingdom's style, I've got a mixed bag of the two kingdom's graphics in my city.  The walls and that first building are Empires, and the rest is Kingdoms.  Is this how it is supposed to work?

Here's the screenshot: