This is on the What devices are Unlockable Page
What devices are supported by the Bootloader Unlock program?
Supported Devices
The following devices are part of our initial roll out of the bootloader unlock program; additional devices will be added progressively.
Photon Q 4G LTE Sprint
Other Supported Devices
Previous devices released with an unlockable bootloader, and supported through Motodev at the following URL:https://developer.motorola.com/products/bootloader/
Motorola RAZR developer edition Europe Motorola XOOM Verizon Motorola XOOM Wifi Worldwide
Based on what I saw on the FAQs, it looks like anything prior to August 2012 will not be on the list. Here is a fragment from one of the questions.
THE STRING "fastboot oem get_unlock_data" DOES NOT RETURN ANY DEVICE ID. WHY?
The bootloader on Motorola devices released before August 2012 is not unlockable. This fastboot command will not return a device ID or unlock data for these Motorola devices. At this point, only the devices on our Supported Devices list are eligible for the unlockable bootloader program.