I don't know about everyone else but in my last 2 trailers the inserts were the pieces cut out to mount the sink. (Under Corian counter sink mounting). As such they are unique in shape. The 2 won't even swap places. Maybe that's why they are not available.
Clif and Millie
Ozzie (half a dog tall & 2 dogs long)
2009 Ford Lariat F350 SRW CC Diesel
2013 Cruiser CF305SK Patriot Edition
I took mine out the first week I had the trailer and store them in the basement , kinda get in the way .
It was a rainy few days at Algonquin Prov park...tarps kept us dry.
Wayne --Belle River (Windsor), Ontario
2013 Sunset Trail Reserve 25RB..
2015 White Chev Silverado 2500HD 4x4 (6.0 l gasser)
2003 Mountain Star 890SBRX Truck Camper