That’s why I said the late 1800s, although I might be a bit off and maybe it is the early 1900s, as they developed a transfer bar or some other mechanism with the advent of double action revolvers that were drop safe and one could carry with a full chamber.
But yes, the old single action style, for sure, you carried with one chamber empty. (I did mention this in another comment above). All of the new versions of these old style guns have newer safety features and you can have a full cylinder.
ETA - and while most revolvers didn’t have safeties, there were of course some that did. There are always exceptions to generalities.
