I have a Focus v1.3 on AT&T, and it was announced that the Mango update was available for me. I got home from work super excited, but when I went to my computer, Zune told me that there was no update.
After a few minutes of googling, I found this link that tells you how to trick/force Zune into letting you have the update, though! It worked for me, so give it a try if you’re in the same boat 
http://www.wpcentral.com/force-mango-update-early-through-zune-software
