For a room? Worth a call.
We were able to have a dining AP discount applied after the fact but it was only because we were too late to show our AP card while picking up our tickets before Hoop de Doo, so they told me to call after the fact. Normally I wouldn't have cared but it was for 11 people so that added up! It was a hard ticketed event that charges full price then refunds the difference once you present your AP card in person, so while it made sense in that case I can’t imagine it would work in all applications.