As common, when trying to find one thing you stumble into another. I came across this manual that had specific dates of updates to models 1896 and 1898 magazine rifles and carbines. Below is the link for this manual, which can be downloaded as a pdf file.

  (You need to Login

Below is a page from this book. I indicated the item showing when bluing of bayonets end, 4/1/1895. There are dates of other changes on pages following in this manual.

  (You need to Login