No one really knows the exact ingredients in WD 40 because it's kept a trademark secret however regular WD 40 does not contain any silicone so regular WD 40 is not a silicone lubricant.
Regular WD 40 does not contain any kerosene, water, graphite, or chlorofluorocarbons (CFCs) or any Silicone.
Although you can buy another type of the WD 40 which does contain silicone and is a silicone lubricant.
It's called WD 40 Water Resistant Silicone Lubricant and also works great when you do want silicone lubricant but you have to purchase the special WD 40 made with silicone lubricant instead of the regular WD 40.
I've used both regular WD 40 and the Silicone WD 40 and they both work great.