I'm not exactly sure I understand what rough item you're refering to. Different from the Yubikey 1, the thickness of the Yubikey contact is now extremely well defined which makes it seat more properly in the USB port. Are you referring to the sides of the contact ?
Regarding the two-button functionality, we only configure configuration #1 and the Yubikey2s therefore behave exactly as the Yubikey 1s. The second configuration is open to be set for own experimentation.
If you haven't seen it yet, please have a look at the Yubikey2 manual:
http://www.yubico.com/files/YubiKey_manual-2.0.pdfThe new configuration tool is available at
http://www.yubico.com/developers/personalization/Please let me know if I've got it all wrong.
With the best regards,
JakobE
Hardware- and firmware guy @ Yubico