I'm going to say 1900-1920's. Yours, with the tapered end, reminds me of a laborotory fitting with a rubber tubing running from the fitting to say, a bunsen burner. Those can still be found in some labs.
I've seen light fixtures with BOTH gas and electric fittings. Those were later and when electricity was more widespread, the gas fittings were eliminated all together from lighting fixtures.
Scott