To add, I am not dismissing the American connection entirely simply pointing out that without a picture, it is tough to say for sure. Here are some 1840 contracts to the US government in 1840.
US Government 1840 Date: 27th August 1840
To: Schnitzler & Kirschbaum
The following swords having been ordered in 1840 were delivered in October 1841 and invoiced in December 1841.
2,000 - Privates' light cavalry sabers
500 - Privates' horse artillery sabers
50 - Officers' horse artillery sabers
1,000 - Noncommisioned officers' swords
500 - Musicians' swords
100 - Infantry officers' swords
The cavalry sabers (1840 model) are marked S&K on the ricasso, bear Prussian inspectors marks and do not have US inspection marks as this was preformed by the minister in Berlin. The scabbard has S&K stamped on the Drag. (Information courtesy of 'Book of Edged Weapons' by ASOAC, pg 58/59)
If we also look at Hicks slim book on Ames contract swords, the S&K figures surface again along with the 39 trial swords purchased in Berlin. Does that make your sword one of 1,039? I dunno
It is evident though that your sword is older than the end of the American Civil War.
Now, if we go to those contracts and compare them to US government specifications, that 1840 contract for 1,000 swords is not listed to have been for wire over leather. Then you have S&K selling to Tiffany and other retailers up as late as 1864. Now think about that. Tiffany, New York, federal. Not an absolute but more meat on the bones for federal use than any CSA purchases. Prewar being used by the CSA? Anything is possible. In puling Norm Flayderman's book off the shelf for American Swords of the Medicus Collection, there is not one example of a leather on wire except for an example such as I posted above, The root of the swords essentially the French 1816 pattern that lasted up into the twentieth century with modifications over time. is the Medicus collection a complete line up/ Probably not but the fellow had gone to great lengths in collecting "one of each" and I find myself quite often seeing a sword there not to be found elsewhere.
I also have images of oddball Ames assemblies that include different handle materials for the basic hilt and not to forget the general officer swords deemed by the US that look a great deal like the 1840 nco. However if we look at the US contract for the swords It is true that Ames was the only contractor for the 1840 nco swords until the outbreak of war in 1861,
A picture of your sword would establish that it is a spadroon blade (ala the US 1840 patterns) and not a broadsword or epee type of blade.
S&K were agents and exporters with dealings before the Napoleonic war They ran as partners from 1787-1864.
Cheers
GC
Note also that I specifically wrote that "maybe the source is just a bit off in their appraisal". Nothing more, nothing less.