I acquired a one-piece S1 rear bumper that does not have the plate light cut-out.
The seller told me that it was mounted on only few very early S1’s.
Does that story check out?
The parts book doesn’t show one piece bumpers without cutout, only three piece ones came with or without.
Only the late models came with the lamps in the ugly (sorry) handle.
But Canada, USA and Germany didn’t get the wings around the door lock (according to the parts book), the alternative is not even listed so in short I tried but don’t know.
That’s my experience as well. I’m no eggspert in ROW, but in the US the earliest cars could have one-piece bumpers, but with the cutout. The 3-piece were around by 1970 if not earlier, with the cutout. In 1973, last year of the S1, the US (but not ROW) bumper centre section lost the cutout, and the number plate light was moved to a plinth. The same plinth (or ugly handle as David says) was introduced in S2 ROW production, and remained for S2 US production–so we were a year early. We were also a year early for the two-colour taillights. Daimlers followed suit. When they lost the bumper cutout the number plate lights moved above to a fluted plinth. The earlier Daimler S1 cars had a similar plinth but without provision for the lights.
Bottom line, I don’t know what you have but it’s interesting. Probably not relevant but you can remove a 3 piece bumper and it will appear to be one piece if you do not remove the overriders.
It’ll be from a S1 Daimler these had the number plate lights in the surround from the beginning if I recall correctly