I've seen them on a few of the early/mid 1950s 3-speeds, mainly the Travelers with stainless fenders, bags and lamp sets. They looked to be correct on the ones I saw - no obvious evidence that the wheel was torn apart and the Dynohub added later. I can only think of a few examples I've seen and most either didn't have a lamp set or had a bottle/Miller type set up. I suppose it's possible they were an upgrade you could specially request at a bike shop rather than from the factory, but they looked on-period from what I saw of the bikes.