While the Cr-48 was a device for people to use, (Mobile Lab) is a specialized tool for developers to test other devices. Wyvern is a specific board name or platform used within this infrastructure.
Here's a detailed comparison of the two devices: google cr-48 vs wyvern moblab
This comparison looks at two very different technologies within the Google/Chromium ecosystem: the Google Cr-48 (a pioneering 2010 notebook prototype) and While the Cr-48 was a device for people