I expect he is correct about a selloff, but I believe the timing is more dependent on the amount of civil unrest. If there are more disturbances like the looting in Chicago last night and this morning throughout the fall, those shotguns will stay in homes. If things calm down as they should as temperatures cool, those firearms should hit the market.
I have shotguns on consignment with a local dealer and sent a whole bunch of pistols to my liquidating dealer in Texas to fund a 9x23 SVI six-inch wide body and a WC EDC X9. Prices on the higher-end stuff do not really drop. But the prices will fall on the stuff I am selling.