Understanding OOB

[The_General]

I'll try to help but oob's files are completly locked ie. any alteration of the file sooner or later will cause problems with the scenario that uses it.
Recently I changed ONE leader picture no. in Vicksburg game and after some time I couldn't open any of Chickasaw Buff's scenario.

Command-leadership-?number id.?-name
L 2 4 187 Col Brockenbrough

L - leader
2 - command rating
4 - leadership rating
187 - picture no. (in leaders.bmp file)
- rank and name

Unit type-Strenght-quality-???-weapon-??-??-Unit name
U 617 4 M R 15 12 11th NC

U - unit
617 - strenght
4 - quality
M - ?? maybe it's unit type as zouave regs have Z here, but why 11th NC has M?
R - weapon
15 - guess it's unit's picture (from units.bmp)
12 - ??
- name