Not with-in the Capital building, but many were carrying outside (in violation of DC law AFAICT):
> Video footage reviewed by prosecutors also suggests Munchel and his mother carried weapons while in Washington, DC — despite the district's strict gun laws — and abandoned them only before they got into the building.
> "We're going straight to federal prison if we go in there with weapons," Eisenhart told Munchel before they entered the Capitol building, according to prosecutors.
> "We can put 'em in the backpacks," Eisenhart then said, before stashing "tactical bags" outside the building, according to prosecutors.
* https://www.insider.com/zip-tie-guy-capitol-riot-plastic-han...
> None brought cable ties with them […]
At least one seems to have:
> Brock was arrested Sunday in Texas after being photographed on the Senate floor during the deadly riot wearing a helmet and heavy vest and carrying plastic zip-tie handcuffs. The 53-year-old is charged with knowingly entering or remaining in a restricted building or grounds without lawful authority, and violent entry and disorderly conduct on Capitol grounds.
* https://apnews.com/article/capitol-siege-fort-worth-texas-e1...
I am reminded of Hanlon's Razor: never attribute to malice that which is adequately explained by stupidity.
* https://en.wikipedia.org/wiki/Hanlon%27s_razor
I think a lot of the mob were useful idiots and are being manipulated via populism by those with an actual clue. Georgia just passed the voter restrictions under the popular 'support' of these folks.