Can iPhone 4 Facetime through Cellular without Wi-Fi?

Question above

I don't think so. I have the phone and it has never worked for me.

No. Only the iPhone 5 can

IPhone4s would; iPhone4 would not. I do not understand why that would be the case. Video calling was supposed be one of the 'selling points' of 3G; iPhone has been 3G capable for long. There's setting though, inside of face time settings, where you have to enable 'use cellular' to be able to use face time over cellular connection.