No, silk road did not sell weapons. There was legal content like pornography and other media on there, but Ulbricht was an idealist and excluded material with "intent to harm".
So all the people who got convicted for selling firearms on Silk Road, how'd that happen then?
Notably, as Ullbricht predicted, the Silk Road was immediately replaced by sites which did not have such ideals, and openly sold weapons and illegal pornography.