State of Alabama records show that prior to secession Governor A B Moore purchased 300 Smith carbines from Poultney & Trimble of Baltimore MD. Also find reference to purchase of Smith carbines for the "Palmetto Hussars" of Beaufort District SC about the same time.
http://books.google.com/books?id=8IAY95_azRQC&pg=PA301&lpg=PA301&dq=%22Gilbert+smith%22+carbine+1860&source=bl&ots=41xkXbB-QK&sig=MduJLb3WoELM-AgCUEdT-37G_44&hl=en&sa=X&ei=lVTPULLBBs_TqQHE6IGoDw&ved=0CC8Q6AEwADgK#v=onepage&q=%22Gilbert%20smith%22%20carbine%201860&f=false

Most accounts of Smith carbine production mention a latter date, usually 1863. What evidence can be found of earlier production models? Thus far I have found only this --

"As American Machine Works became a subcontractor to Massachusetts Arms Co. by manufacturing Smith’s cavalry carbine under Gilbert Smith’s Pat. # 15,496 issued Aug. 5, 1856, the Massachusetts Arms Co. Ledger Book covering the period from October 1849 to April 1868 reflects that production costs for the Smith Carbine began to be recorded in April 1860, and revenues began to be received from Poultney & Trimble shortly thereafter. However, entries for American Machine Works did not appear in the accounts until February 1864, with the last entry dated in October of that year."

John D Hamilton, Arms Makers in the Pioneer Valley.
http://asoac.org/bulletins/94_hamilton_makers.pdf

Also, is there a published source which reports issues of Smith carbines to Federal units?