UL698A builds on UL508A. So you must start there. My reading of UL698A only adds a few additional labels beyound what 508A requires.
As far type or construction of labels or tags, 508A only say this
"....shall be made by die-stamping, silkscreening, or etching in metal or plastic or with an indelible ink on adhesive-backed label stock and permanently attached to the industrial control panel by rivets, screws, or adhesive."
although what SG-1 only makes sense, the standard does not specifically require it.