How to identify iPhone GSM, CDMA, GSM + CDMA

Check the Model no. at the back of your iPhone and verify with these following model numbers :

A1457, A1530 – iPhone 5S (GSM) 
A1453 – iPhone 5S (CDMA)

A1533 – iPhone 5S (GSM + CDMA)

A1507, A1529 – iPhone 5C (GSM)
A1456 – iPhone 5C (CDMA)
A1532 – iPhone 5C (GSM + CDMA)

A1428 – iPhone 5 GSM (standard GSM model in USA for AT&T, T-Mobile, etc)
A1429 – iPhone 5 GSM & CDMA (normal CDMA model in USA, Verizon, Sprint, etc)
A1442 – iPhone 5 CDMA China

A1387 – iPhone 4S, CDMA & GSM
A1431 – iPhone 4S GSM China

A1349 – iPhone 4 CDMA
A1332 – iPhone 4 GSM

A1325 – iPhone 3GS China
A1303 – iPhone 3GS (GSM only)

A1324 – iPhone 3G China
A1241 – iPhone 3G (GSM only)

A1203 – iPhone (Original model, GSM only)