According to one reader from Droid-Life, they picked-up an update to Jelly Bean on their Verizon Motorola XOOM. The update moved his XOOM to build number JRo03H, which is the newest update officially available. You can take note of the baseband for confirmation that it was indeed on the Verizon branded device.
Could Verizon have put it in the system for a brief moment by accident and then pulled it after some people got updates? Maybe Verizon let a few loose in a tester situations ahead of their schedule. Anything is possible. Until we hear official word from Verizon and or Motorola, we will file this one as a lucky user once of scenario.