Welcome to the JOF.
I don't have any info, but I do have a question: Wouldn't the sink insert/covers be part of the sink no matter which countertop was installed?
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.