Absolutely. They obeyed D.C.'s gun laws because they wanted access to the Capitol and knew brandishing/carrying would have given DC Police immediate cause to arrest them at their rally point at the Ellipse (or sooner). And they didn't want to be convicted and punished for violating those laws, which at a minimum have you looking at a potential year in jail and/or $2,500 fine for unlawful carrying.
It gives complete and total lie to the NRA's perennial claim that "criminals don't obey gun laws." On January 6, most of them did--to save their own a**es!