I would consider it a bug in the documentation. What I can tell you is that at this given moment, the S2C hardware with the available firmware that has been released, supports either the Zigbee or 802.15.4 standards ONLY.
Yes, that one is capable of being loaded with the Digi Mesh 2.4 Code. You can also just order the module with the Digi Mesh code on it. The part number would be XBP24-DMWIT-250