I'm looking to book SQ Premium Econ from SIN to DEL later this year, and as a KF *G passenger, I see I can pick any seat for free except the extra legroom seat.

My question is do they ever release these seats for free (say T-96 or 48 hours before, at check-in), or will I always have to pay to select it? Trying to see if I should bite the bullet now and snag it or gamble and see what happens ... thanks all for guidance!