Labels.Font returns stdole.Font object. This object has no Style property. You must individually access Labels.Font.Bold, Labels.Font.Charset, Labels.Font.Italic, Labels.Font.Name, Labels.Font.Size, Labels.Font.Strikethrough, Labels.Font.Underline, and Labels.Font.Weight.
Also please note that the interop wrapper for visual controls will instead provide a typical System.Drawing.Font.