You asked, Yes a regular CSA guy. Always in Clay County, I don't think related to Long family in Moniteau Twsp Howard County.

Name: Peyton Long
Death Age: 23
Birth Date: 26 Mar 1841
Death Date: 1 Mar 1865
Interment Place: Missouri, USA
Cemetery Address: Liberty,MO Liberty, MO 64068
Cemetery: Fairview Cem
Notes: Capt Asst Qtr Mr Confederate States Army

1850
Name: Peyton Long
Gender: Male
Race: White
Age: 9
Birth Year: abt 1841
Birthplace: Missouri
Home in 1850: Fishing River, Clay, Missouri, USA
Attended School: Yes
Line Number: 37
Dwelling Number: 1324
Family Number: 1324
Household Members Age
Lanard Long
41
Frances E Long
38
Susan F Long
12
Peyton Long 9
Cordelia Long
6
Elizabeth Long
3

1860
Name: Gayton Long
Age: 18
Birth Year: abt 1842
Gender: Male
Race: White
Birth Place: Missouri
Home in 1860: Liberty, Clay, Missouri
Post Office: Missouri City
Dwelling Number: 369
Family Number: 368
Household Members Age
Garard Long
52
Francis Long
49
Louisa Long
20
Gayton Long 18
Cordelia Long
16
Mary Long
12
Bermon Long
7
Jadora Long
Michael Harley
28

RANGER CAPT, Quantrill's Co, Quantrill's MO Partisan Rangers....joined Quantrill in summer 1863. Was at Lawrence KS, Baxter Springs on October 6, 1863, Fayette on September 20, 1864 and Centralia on September 27, 1864. Killed on the Bewleyville-Webster Road in Breckinridge County, KY, near modern Irvington. A.D. "Donnie" Pence badly wounded, but saved by Frank James, who called the town "Buelahville." Pence later sheriff of Nelson County, KY. Obviously part of Quantrill's group to Kentucky at end of war. Find a Grave:
https://www.findagrave.com/memorial/17279413/peyton-long?_gl=1*vd1ttj*_ga*MTM4MjY3NDA3Ni4xNjU2MzQyMjUy*_ga_4QT8FMEX30*MTY1ODk1ODIxNS41LjEuMTY1ODk2MDM4MC4w