Not unusual in the slightest. LOG ("lever over guard", aka Jones underlever) hammerguns were common until WWI and lots of makers continued to offer them into the '20s & '30s, although most of the later guns were top-lever. Quite a few hammerless guns, especially rifles, were built on the Jones action as well. Purdey seems to have been especially fond of them, as they built "best" hammerless sidelock nitro express DRs on the Jones until 1914 at least. Some of these were even built as snap actions.
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