Very similar to what Ken has said, 2 tabs at the front corner of the seat then left the front of the cushion and pull forwards. The back has one fixing at the bottom centre once removed the lift vertically to release the top hooks. I'm putting mine back together now.

Hope it helps
Tom

I can't speak for a '33, but on my '32 the rumble seat cushion
lifts up at the front and slides forward to bring two tangs
away from their hold down at the rear of the cushion.
This will expose two screws/bolts on the bottom of the seat back.
One on either side at the bottom. Remove them and lift the seat back up.
Hope this helps.
Ken

Pretty quiet here. I hope someone can answer. . .

How is the rumble seat cushion removed in my 33 PD? Appears securely attached, and I don't want to accidentally break something. Thanks in advance for any help.