I have the R6 calipers on my YPVS. Blue dots. They work great with EBC HH pads. I did have to go to a FZ1 master cylinder . The stock YPVS felt weak. The FZ1 has the same blue dots and the master cylinder looks stock on the YPVS.
Gold have aluminium pistons. Blue have steel - they do rust. Silver spots are reputed to have stainless pistons, but I have found ordinary pitted steel ones in one I stripped. Unless radial mount, they are all 100mm between centres and interchangeable (bleed nipple and banjo placements differ between models). Easy to strip and rebuild.