No, you lose the boost on all staked TGLD if you unstake any amount.

From TGLD mechanics: The presale yield boost is grandfathered to your wallet. If you unstake even 100 TGLD (regardless of restaking more), you permanently lose ALL boosts. The remaining 1000 TGLD would then earn only the normal public APR, not the boosted rate.

This rule prevents partial unstaking while keeping boosts. For details: TGLD Presale Mechanics