At least in Austria and Germany "Does anyone recognise these switches and can tell me where to get spares?" is a fairly common question. Designs rarely last more than say 20 years, sometimes less, and replacement covers usually need to match quite exactly to fit even physically, let alone visually. Occasionally manufacturers re-design even the switch mechanisms enough to make them impossible to replace.
Actually it's more like the other way round - when a 1987 Siemens switch shorted out (well to be more precise the wiring between the switch and fixture shorted to earth and the switch contacts welded themselves shut) and burnt at my parents' office I was seriously surprised I could fit the old covers to a new switch! I'd have hated to replace an entire vertical bank of 8 individual switches!
