[I have transcribed the text below.]
According to a letter written by Sinex in March 1864, 22 officers and 276 enlisted men (excluding pioneers and musicians) were engaged in the battle.
At least one man listed on the plaque was almost certainly not there: Henry Linkerman (D) deserted on the march to Gettysburg, on 30 June 1863, and apparently did not return until 11 March 1864.
Thanks to Ross Johnson for this picture!

Transcription
Note that twelve men were initially listed on the plaque and later deleted; I have restored their names from the card with the original plaque, and marked them '[deleted]'
- headquarters (9 members)
- company A (50 members)
- company B (19 members)
- company C (33 members)
- company D (36 members)
- company E (47 members)
- company F (24 members)
- company G (22 members)
- company H (23 members)
- company I (16 members)
- company K (19 members)
[Headquarters]