Hi Brian Mila,
Usually we don't support backwards conversion of the skins. That siad, some of RadControls don't have much rendering changes and will work directly with older releases - RadComboBox is one such control. Others though require more changes to support the old releases. We can convert some of the skins for you, but we will need you to open a support ticket and list the RadControls you use and need WebBlue for. Thank you in advance.
the Telerik team