Yeah I looked at my co worker's TP battery and its the exact same battery. HTC didn't make the Diamond bigger to fit the battery in. The fit the batter to the CDMA Diamond because it gobles up more juice than the GSM diamond so they needed the larger battery
What gets me is that the TP didn't get the larger battery treatment, maybe a 1,600mah or 1,700mah battery instead of the 1,356mah that we get. It is a larger phone with more hardware.