This is going off of iFixit data. According to a report ... These are the iPhone 4, iPhone 6, iPhone 5, iPhone 4s, iPhone 5s, iPhone 3G, iPhone 3GS, iPhone 6s, iPhone 7, iPhone X, iPhone 6 Plus ...
The above photo shows you the logic board of the three (WiFi up top and 3G below the ruler) but iFixit also documents the other key ... the hardware for both the CDMA and GSM iPad 2 follows the iPhone ...