Traditional? Only in the last 40 years in which turkey has become widely available year 'round (and cooked and 'preformed" turkey showed up on your sales sheet). The type of restaurants in which club sandwiches were regular menu items (and recipes from early cookbooks) up until about 1970 called for sliced roast chicken breast. From purveyors, poultry markets and grocery stores, turkey was almost a "specialty" item, stocked in bulk for cafeterias, buffets and similar venues in which T&D was a regular feature.