All Champion Mondial frames have 531 double butted tubes.
Only ladies step through frames and 70cm frames bad plain gauge seat tubes (some custom built frames have PG top and or down tubes).
And 753 came with 753 and Columbus with Columbus tubing of course.
Trophy, Formula, TdF, Vuelta and some other, cheaper, non Champion Mondial frames were built with 3 tubes 531 plain gauge and cheaper alloy steel forks and stays.
All Champion Mondial frames have 531 double butted tubes.
Only ladies step through frames and 70cm frames bad plain gauge seat tubes (some custom built frames have PG top and or down tubes).
And 753 came with 753 and Columbus with Columbus tubing of course.
Trophy, Formula, TdF, Vuelta and some other, cheaper, non Champion Mondial frames were built with 3 tubes 531 plain gauge and cheaper alloy steel forks and stays.