Was surprised to learn that not all 18 size top grade model 92 Vanguards are lever set. Some stem set open face case 92 models were made stem set until 1903. Here is one that is the first Vanguard production run made in unrecorded 21j not 17.
My remaining question is its ruby jewel marking. Other six all different 92 Vanguards I have are not. I like best a 17j hunter 7001281 about a year newer recorded as a 21j. Which is apparently all ruby jewels but not marked.