This is the first I've heard that Formbys and Minwax Tung Oil finishes do not contain Tung Oil. Seems to me the Formby's can lists Tung oil as one of the ingredients. I thought both actually did contain small amounts of Tung oil. Confusion results because these are varnishes and don't give you a real oil finish. Same thing with Tru oil (another varnish)- does not give you a true oil finish. Varnishes are ususally a mixture of oils, resins, and drying agents. If you want to do a real, hand rubbed oil finish, steer clear of these and other "oil finishes". I use BLO or Tung to finish my stocks. Apply in thin coats (I cut the first coats to a 50/50 mix of oil and turpentine/mineral spirits), rub in well, wipe off excess, allow to dry, rub back lightly, repeat, repeat, repeat.......
But then that's just my preference.