In all likelihood it is a mid seventies bike. When the bike boom started in 1971 Falcon ramped up production and boatloads were imported to the U.S. Especially red ones. A Falcon Black Diamond with aluminum rims, cranks, centerpull brakes, stem, and bars compared favorably with it's European competition in the $125 entry level range. It outshone a similarly priced Schwinn at that time. I wouldn't sink too much money into as it's not a great frame but if its very thin paint, decals, and components are in good shape it can be cleaned up to be a nice looking bike.