Where to find OEM-quality seat bottoms for 2000 Sport Nautique

[jbosse1]

I need to replace the three individual seats (just the bottoms) on my 2000 Sport Nautique. I see vendors who supply "skins". Where can I find the entire seat (board, cushion, skin)? I am looking for OEM or OEM-quality after-market. I have attached a picture. Does the shape of that middle seat look correct? Was the factory seat tapered to align correctly with the side seats? The gaps on the "straight" middle seat look terrible to me. It makes me think that it was replaced.

Thanks in advance for your help!