I googled Whale Pumps and got to their website, which I found useful when I had to rebuild my galley foot pump for the fridge. I found a parts document (attached). On page 3, there's a part # " DP8904 Plastic deckplate kit with lid" that looks like it might be what's on our boats. I contacted their customer support and they were most helpful; you might want to give them a call and see if that's the right part.