you can always appeal and add the test scores as ‘new information’. But I’m afraid that the appeal reviewer may not take kindly to, ‘I forgot’, as the reason for not submitting test scores. Even if you use the LD angle, that only raises the question about being able and responsible enough to complete work at the major research university. But definitely speak with your GC. Perhaps they’ve had experience with other kids who forgot…
As an example of the appeal process, I’ve added a link to UCLA’s: