Sort of... the game had STI staff on board but it was still designed mainly by Sonic Team members (working in the US). The second Sonic Team USA was similar, just Sonic Team staff relocated to California. Here's the Sonic developer breakdown...Mama Smurf said:STI (Sega Technical Institute) made StH 2 and, while they are based in the US, as far as I know they have little (nothing?) to do with Sonic Team USA.
Sonic Team
-Sonic the Hedgehog (SG/mobile)
-Sonic Jam (SS)
-Sonic Adventure (DC)
-Sonic Mega Collection (GC)
-Sonic Advance 2 (GBA)
-Sonic Battle (GBA)
-Sonic Mega Collection Plus (PS2/XB)
-Sonic Gems Collection (GC/PS2)
-Sonic Rush (DS)
Sonic Team/STI
-Sonic the Hedgehog (PC)
-Sonic the Hedgehog 2 (PC/SG)
-Sonic the Hedgehog 3 (PC/SG)
-Sonic & Knuckles (PC/SG)
Sonic Team/Traveler's Tales
-Sonic 3D Blast (PC/SG/SS)
-Sonic Blast (GG)
-Sonic R (PC/SS)
STI
-Sonic Spinball (GG/SG/SMS)
-Tails and the Music Maker (Pico)
Sonic Team USA
-Sonic Adventure 2 (DC)
-Sonic Adventure 2 Battle (GC)
-Sonic Adventure DX: Director's Cut (GC/PC)
-Sonic Heroes (GC/PC/PS2/XB)
-Shadow the Hedgehog (GC/PS2/XB)
Sega-AM2
-Sonic Championship (AC~ Model 2)
Sega-AM3 (later Hitmaker)
-SegaSonic (AC~ System 32)
Ancient
-Sonic the Hedgehog 2 (GG/SMS)
DIMPS
-Sonic Pocket Adventure (NGE)
-Sonic Advance (GBA)
-Sonic N (NGE)
-Sonic Advance 3 (GBA)
SIMS
-Tails' Sky Patrol (GG)
Hudson Soft
-Sonic Shuffle (DC)
Jupiter
-Sonic Pinball Party (GBA)
Compile/STI
-Dr. Robotnik's Mean Bean Machine (GG/SG/SMS/mobile)
Orion Interactive
-Sonic Shcoolhouse (PC)
Other Internal SOJ teams
-Sonic The Hedgehog (GG/SMS/mobile)
-Sonic Eraser (MD)
-Sonic CD (PC/SCD)
-Sonic Chaos (GG)
-Sonic Drift (GG)
-Sonic Game World (Pico)
-Sonic Triple Trouble (GG)
-Sonic Drift 2 (GG)
-Knuckles Chaotix (32X)
-Sonic Labyrinth (GG)
-Tails Adventures (GG)