Quick response which hopefully answers your question: Too lazy to look up the exact time span, other than it was roughly 9 months during 1900 (225000 - 250000 or so) during which time that cocking piece was used on new production rifles and carbines. Years ago, before Mallory & Brophy, it was though to be "correct" only on M1899 carbines, but that was proven false. Interesting but not rare, and, having caused more problems than it solved, use was dropped.

Thanks for the responses.  This rifle is a 1903 build so the bolt's probably not original.  Someone ground down the front area of the bolt sleeve to make clearance for the Lyman receiver sight.  They also put her in a modern Bishop stock.  Sort of like putting heels on Daisy Duke.  Wait, that actually sounds pretty good.  Anyway, she is a candidate for a new barrel and a CMP legal configuration.