We ran into this issue a couple times; once with the Granite composite kitchen sink by blanco and once with some bathroom sinks. We decided to try plumbers putty instead, cuz using nothing didn’t make sense! it worked alright on the kitchen but the bathroom sinks actually worked better with nothing! My advice- try it. If it leaks, try the other way.

Silicone bleed and very well may discolor your sink permanently.

I replace sinks for a living and never use plumber's putty because virtually all of the sinks I remove that were installed with it leak. I've heard that the government made the manufacturers take out the stuff that kept it pliable.

I've set hundreds of composite sinks with silicone and never had a bleed. Sink manufacturers recommend installing their sinks with clips that are junk and leak (seen it a million times) and recommend a 36" cabinet for a 33" sink which is silly too. A 33" sink undermounts into a 33" cabinet just fine with straps. Manufacturers don't always know of what they speak.