Silkie combs and wattles are not a good way to judge gender, especially if they come from show stock. While male combs will be larger than females, many breeders aim for as small a comb as possible. Personally as long as the comb is properly shaped, I do not care how large it is--but it does seem that the most grotesquely shaped ones are the ones that tend to be largest
Anyways, I digress; a good quality silkie should have teeny, tiny or even absent wattles. This applies to both genders. Even non-bearded silkies have considerably smaller wattles than are present in more common barnyard breeds (leghorns, plymouth rocks, orpingtons, RIR, etc.)
The pubic bone spread is a pretty good way to distinguish genders, but is not always accurate. In addition to spacing size, the flexibility of the spacing should be taken into account. A pullet's bones can and will spread a bit as she lays her egg; a cockrel's bone have no need to spread apart, and are less flexible. (Be very gentle, if you check this.) Also, since the birds come from show stock, chances are that pretty good that they will mature onsiderably cmore slowly than hatchery birds. I wouldn't expect obvious appearance differences to show up until the birds are close to six months or even more. And the pullets probably will not lay until they are 9-10 months or more.