Is there a certain drop rating for...

[Tsunami]

There's a certain drop rate for enemy parts for all Section ID's.

I'll list Oran:

Episode 1
Enemy part (In yellow)/ Location (In green) / Drop rate (In red)

Booma's right arm/ N, H, VH-Booma/ N/H/VH: (Not sure)
Gobooma's right arm/N, H, VH-Gobooma/ N/H/VH: (Not sure)
Hildebear's head/ VH-Hildebear/ VH-1/44
Hildeblue's head/ H-Hildeblue/ H-87.5%
Rappy's wing/N, H, VH-Rappy/ N-1/7282 H/VH-1/128
Dragon's claw/ULT-Sil Dragon/ ULT-1/57
G-Assassin's Arms/N, H, VH- Grass assassin/ N-1/10083 H-1/128 VH-1/117
S-Beat's arms/ VH-Sinowbeat/ VH-1/107
Delsaber's Right arm/ N-Delsaber/ N-1/5852
Delsaber's Left arm/ H, ULT-Delsaber/ H-1/183 ULT-1/456
Sorcerer's Right arm/ ULT- Gran Sorcerer/ ULT-1/901

Episode 2.
Gi-Gue's body/ ULT-Gi-Gue/ ULT-1/394
Gal Gryphon's wing/ ULT-Gal Gryphon/ ULT-1/57