The one I've been using and have ordered two more of is labelled as XBee S2, but the full model is XB24-Z7WIT-004. Here’s how to break down the full model designation:
Series 1 (802.15.4) or Series 2 (ZigBee) XBees
XB24- = non-Pro version
XBP24- = Pro version (higher transmission power)
Shipped Firmware type
A : 802.15.4 (for series 1)
DM : Digimesh (for series 1)
B + something other than Z7 : ZNet2.5 (obsolete firmware for series 2)
Z7 : Zigbee (for series 2)
BZ7 : Zigbee (series 2B module)
CZ7 : Zigbee (series 2C module)
DZ7 : Zigbee, thread-ready (series 2D module)
Type of Antenna
CI : on board ceramic chip
PI : PCB (trace)
RI : RF pad
SI : RPSMA connector
UI : U.FL connector
WI : wire whip
T : Thru-hole
S : Surface Mount (SMT)
-001: series 1 module
B003: series 2 programmable module
-004: series 2 module
Note: The above breakdown doesn't include the new XBee 3.
Since you're looking at a 3-pack kit, it's unclear which antenna type it is but the photo tells me they probably have the U.FL antenna. Otherwise, they are the series 2C programmable type of module. Besides that the main difference from the model I got is that the transmit power is stronger (3.1 mW for the S2C, which will probably be a good thing for you! Anyhow, this means the included model is likely the XB24-CZ7UIT-004.
Whether the module is programmable or not is not a big concern unless you are planning on adding some kind of device to give the XBee module a function beyond being Zigbee repeater. The programmable modules allow a compact system to run directly on the module itself instead of needing to connect the module to a Raspberry Pi, etc., to turn the module into, for example, a temperature sensor.
Be warned that on DIGI's website, the XKB2-Z7T-WZM kit information shows it contains two TH (through-hole) modules and one SMT (Surface Mount) module. They should work the same, however.
Getting 3 programmable modules with DIGI branded USB host boards and the USB cables for $89 is a great deal though. I got my first S2 new on eBay for $16 and a 3rd party (Waveshare) USB host board for $14, which of course would scale out to $90 for three sets. But I never would have spent $90 up front without first testing one XBee to make sure it would work. Careful spending and strict budgeting are reasons why I am able to be a homeowner in the first place. But that's just my situation.
As for powering and mounting the units, they require a USB power source, so I plan to "hide" them discretely in spots where I have power strips with USB ports. I may put them into a DIY case (there's a laser cutter at my work), and then mount them under furniture or something like that. I'm not too worried about it because they're so small - and I'm divorced so there's no WAF for me!!
When I get my other two XBee modules, if people are interested, I can post instructions with screenshots showing how to connect and configure them, and use one to map your mesh.