CIVIL WAR CONFEDERATE VETERANS? KEPI HAT, Circa 1870-90 per APPRAISAL For Sale

This hat came out of an estate. The owner had a small private museum which contained items from the Revolutionary War through WWII. I had this hat appraised by a militaria expert at an online appraisal service, Value Your Stuff, and their information is listed below:
Valuation reference:V76234-4
Guarantee line:CSA Artillery Kepi, Probably Post War
Description:Material content - Wool with leather visor. Wide brim denoting artillery. Two CSA brass buttons. Linen cover or recover of interior. Uniform sewing of inner sweat band appears to be machine sewn.
Date:1870-1890s.
Height:5 inches
Length:11 inches
Diameter:6.5 inches
sale Value:$1,500 - $2,000
Insurance Value:$3,500
Extra Notes:One of the most difficult items to appraise are Confederate uniforms and headgear. Potential quite valuable, there are many examples extant of fraudulently aged more modern pieces as well as original post Civil War \"veterans\" uniforms worn in Memorial day and other holiday events.It would appear from the photos alone that this as a post CW kepi with some age. There appears to be some relining and possibly sweat band replacement or repair. If some documentation/provenance exists to attribute this to an actual Civil War soldier, this would add some form of authenticity.
Proper authentication would be somewhat costly by museum or specialized dealer but the upside, if original, would be worth it.