To show the full UID of your Untangle appliances in Command Center, click on Account > My Account in the upper-right corner of the screen.
On the left side of the page, click on Settings. In the middle of the page, under User Interface, you'll find a checkbox labelled "Mask UIDs". It is enabled by default; disable it and and click Save located lower on the page, under Choose Theme.
Refresh your Command Center session for the setting to take effect.