All chicken have spur buds...so no good for determining gender on chicks.
Males don't start really growing out the spurs until at least sexual maturity(4-5 months),
they don't get significantly larger than a pullets until older than that.
No problem. I had some silver campines for awhile. They can be a little flighty but otherwise a really fun breed. I could be wrong but I think they are also the only chicken that the hen and the rooster feather out exactly the same. That being said I would wait until I was positive if it were hen or roo. They can look identical until they are almost fully mature.