To see upgrade info in your city, look for the blue 'Upgrade Available' arrow to appear over a building. If you have or get any of the data I'm missing, please send it to me in an Inbox message titled, 'Upgrade Info'. I've also entered the upgrade info I've been able to collect since starting this project. If you see any that are wrong, let me know, and I will correct them. I was able to remember the name of some of the upgraded buildings, but some may not be correct. Since I've been on CW for 7 months, I upgraded most of my lower tier buildings long ago, before I realized the need for Tier Level info. Below, I've posted the chart with the info I've been able to collect so far. I'm compiling a chart of all buildings that can be upgraded, which lists the original building name/ Tier Level, cost to upgrade, and name/Tier Level of the upgraded building. Upgraded buildings information, while somewhat difficult to get, is available. Currently there is no place to get Tier Level information for them. Custom buildings can only be obtained as VIP Monthly Challenge Rewards.
There are two types of non-listed buildings: 1) Custom buildings, and 2) Upgraded buildings. A number of players including me, have posted here in another thread asking CW to give us a way to find the Tier level of buildings that are not listed in the Building Shop.