Kindred said it best. 100% pure silicone toys are ok to use silicone lube. BUT be aware, many toy companies use lesser grade silicone, and/or only use 10% (or random number) of the toy is quality silicone. Do a spot test to be safe.
(I know it sounds confusing but think of it like this. In many marketing ploys, we know Egyptian cotton is a great quality towel. However, many towel or sheet companies, will advertise, "made with 100% pure Egyptian cotton". However; that only means that the actual amount of Egyptian cotton they use (which in some towels and sheets, is only the thread used to sew the edges) is Egyptian cotton. Makes sense?)