How to tell if an S2 has NFC?

[Surfer Joe]

Samsung has reportedly revised the S2 to include NFC.
How can buyer tell if the phone they are buying is one of those or an earlier version without NFC?
Is is an OS feature or does it depend on a hardware difference in the phone?

 

[3waygeek]

There's an app named Z-Device Test in the Android Market; it can detect NFC hardware.

 

[Surfer Joe]

There's an app named Z-Device Test in the Android Market; it can detect NFC hardware.

Thank you, but I was hoping to find out before buying one.
Is there any way to tell from the box or the model number if it is one of the revised S2 with NFC?