I have several (4) LC Smithís with that buttplate, and all are from January 1890 thru January1894, and all are believed to be original buttplates based on their condition, and the condition of the buttstock underneath them.
SN30036 (DOM January 1890)
SN33200 (DOM May 1891)
SN873 (DOM 19 Dec 1893)
SN37382 (DOM January1894)
Itís my hypothesis, along with others on this forum, that the Hunter Brothers purchased these buttplates from a supplier in support of standing up the new factory in Fulton around 1890, as the prior Syracuse NY buttplates were no longer appropriate for guns made in Fulton. (I also believe that the standard ribbed buttplate didnít come into common use until late 1894, early 1895.)
I would suggest that we study more original examples from the 1890 to 1894 time period to build a larger body of evidence to support a hypothesis.
Lloyd, there is a VERY high probability the buttplate is original to your gun. So I would never recommend replacing it.