Well, i found three major solutions with PFM, but unfortunately with some consiquenses:
I URGE YOU TO MAKE BACKUP FOR bg_MM_ZoR.pack and bg_us_wpath.pack, just in case
1) You can just simply make changes in subculture tables (located at bg_MM_ZoR.pack), just change sc_indian_hindu culture to european, but if you do that, both union and csa models on globl map will be the same, cause author made csa and union in different cultures in order to use new separate models of 3.6.2
OR
2)Open the bg_us_wpath.pack, find factions_tables and swap the values of csa and union subcultures, then find agents descriptions in this file and change csa models to indian, and union to european. This will cause in adding drum sounds to union, but deleting them from csa. Use this if you want to have 3.6.2. models working for union and csa correctly.
OR
3)IMO the best way: open the bg_us_wpath.pack, find factions_tables add both factions to sc_european_american, THEN open agents descriptions in this file and delete both union and southern agent description. This will let them both to use drums in battle, but it will revert your map models to those which were in 3.4, they looks pretty too, IMO.
OR
4)Create a new culture. Unfortunately i don't really know how to create it properly, have read some articles on this point, but realized that this will be unacceptable cause of huge amount of changes
I really appreciate the huge amount of work which was done by the author, so i thought that solving the drums problem will help people to experiense full immersion in the game while playing as union states.