Sadly, other than the names of the buildings attempting to indicate what type (zone) the building is a part of, there is no identifier to quickly see which zone-set that a building belongs to.
Seems to me that there's a great place to get that kind of information, though. It would be nice if the EA SimCity BuildIt devs would include zoning visibility in the "Residential Buildings" viewer.
Of course, there should be some way of seeing the zone type when you tap on a building. Even if it was just a letter such as "F" for French, "L" for London, and "T" for Tokyo.
I'm sure that new theme set swill be introduced in the future and now would be a nice time to plan for managing all of the different sets now. 😉