After a few thousand kms they might loosen again and require re-tightening.
My CG needed tightening twice.
Glad that ur problem is solved, another observation related to Cg vibration: always get ur CG's air filter properly oiled when tuned no matter if ur mechanic says oil isnt needed.
Properly oiled filter would help in lowing engine noise and specially vibrations... you will notice very smooth engine at high speeds