A quick kudos to my colleague William Lam (@lamw) for bringing this to my attention.
There is an issue in the new vSphere 5.1 web client when it comes to displaying Fibre Channel World Wide Node Names (WWNN) and World Wide Port Names (WWPN). The WWNN & WWPN are unique identifiers used in the Fibre Channel world. The problem is that the WWPN & WWNN are not rendered correctly in the UI. It is easier to show you an example. Here is a screen shot taken from my own 5.1 environment. Note the WWNN & WWPN – the identifier displayed in the UI is in the format WWNN:WWPN.