GDG- re: 1st day

[MICHAEL DAVIDSON]

You guys are fantastic.  Thank you so much!
   
  The H Co roster in Otis' Second WI history lists under SERGEANT:
Davidson, Roslas E. b Ohio; farmer; s (single); r (residence), Spring
Green; April 24, 1861.  Promoted Sergeant January 9, 1864.  Mustered
 out
June 29, 1864. (pp 342)
   
  If Reed and other sources say he was made sergeant July 1, and the roster above lists the date of promotion as Jan. 9, 1864, does that mean his field promotion was breveted, or had to be confirmed to be official?  Or are only commissioned officers breveted?  Excuse me, I may not be saying this correctly.