I'm damn certain they are. The ones busting windows and invading were wearing their standard black backpacks, all under 30 and looking in need of a shower. And the one at the Speaker Desk looked like one of the Insane Clown Posse out of make-up. Those guys had a huge protest rally on the Potomic last year for the BLM Commies.
I don’t think all of the protestors are Antifa, it might only be a few Agent Provocateurs, but that’s all it takes.