Are we not complicating this matter IMO there is only two types of half an hour fire door, and both can be referred to as fire doors.
a. Certifiable fire doors ( fire door with documentation, labels and/or plugs)
b. Non-certifiable fire doors (fire doors without)
Both are fire doors and can be FD30 or FD30s. The only problem is if things go pear shaped and you may need to identify which group the fire door belonged to. You could use any means of identifying these fire doors if you think it is necessary, however the need for this information is pretty remote.
FD60 fire doors are another matter there are less indicators, maybe thickness, maybe if there is glazing but very difficult, possibly only certifiable fire door should be considered, but always taking in to account how vital these fire doors are to your means of escape scheme.