Yes, when the Second Amendment was penned, private ownership of cannons was perfectly legal and acceptable. Private citizens "loaned" their cannons to the federal government/US Army to use in the War of 1812. They don't teach that stuff in the public/government schools.
regardless....I'm addin at least 1 Cannon to my arsenal , that may be the coolest house I ever did see. Current "arsenal" = slingshots, pee shooter, ball bat , and very bright probe light. Oh ,, and a whistle.