A method comprising: placing an upper shell panel (120; 120'; 120"') between a first section (100; 100'; 500) of a mold and a second section (150; 550) of the mold, the first section including one or more expansion cavities (105a-105e; 105a'; 505a-505e) and the second section including one or more pour cavities (153, 154; 553, 554); delivering a foam-producing chemical mixture (160; 160') into the one or more pour cavities; closing the mold; allowing the delivered mixture to expand within the closed mold and to force regions of the upper shell panel into the one or more expansion cavities; and removing the upper shell panel from the mold subsequent to the expansion of the delivered mixture, wherein: the second section includes a panel face (151; 551) and a pouring face (152; 552) and each of the one or more pour cavities includes openings in both the panel and pouring faces, the upper shell panel is placed between a working face (101; 501) of the first section and the panel face of the second section and covers the openings of the one or more pour cavities in the panel face, the delivering step includes delivering the mixture through the openings of the one or more pour cavities in the pouring face, the closing step includes placing a third section (200; 300) of the mold onto the second section and closing the openings of the one or more pour cavities in the pouring face, and placing the upper shell panel between the first and second sections comprises placing the upper shell in an unfolded condition on one of the working face or the panel face while the second section is displaced from the first section and then placing the second section onto the first section and pressing the placed unfolded upper shell between the working face and the panel face. placing an upper shell panel (120; 120'; 120"') between a first section (100; 100'; 500) of a mold and a second section (150; 550) of the mold, the first section including one or more expansion cavities (105a-105e; 105a'; 505a-505e) and the second section including one or more pour cavities (153, 154; 553, 554); delivering a foam-producing chemical mixture (160; 160') into the one or more pour cavities; closing the mold; allowing the delivered mixture to expand within the closed mold and to force regions of the upper shell panel into the one or more expansion cavities; and removing the upper shell panel from the mold subsequent to the expansion of the delivered mixture, wherein: the second section includes a panel face (151; 551) and a pouring face (152; 552) and each of the one or more pour cavities includes openings in both the panel and pouring faces, the upper shell panel is placed between a working face (101; 501) of the first section and the panel face of the second section and covers the openings of the one or more pour cavities in the panel face, the delivering step includes delivering the mixture through the openings of the one or more pour cavities in the pouring face, the closing step includes placing a third section (200; 300) of the mold onto the second section and closing the openings of the one or more pour cavities in the pouring face, and placing the upper shell panel between the first and second sections comprises placing the upper shell in an unfolded condition on one of the working face or the panel face while the second section is displaced from the first section and then placing the second section onto the first section and pressing the placed unfolded upper shell between the working face and the panel face. the second section includes a panel face (151; 551) and a pouring face (152; 552) and each of the one or more pour cavities includes openings in both the panel and pouring faces, the upper shell panel is placed between a working face (101; 501) of the first section and the panel face of the second section and covers the openings of the one or more pour cavities in the panel face, the delivering step includes delivering the mixture through the openings of the one or more pour cavities in the pouring face, the closing step includes placing a third section (200; 300) of the mold onto the second section and closing the openings of the one or more pour cavities in the pouring face, and placing the upper shell panel between the first and second sections comprises placing the upper shell in an unfolded condition on one of the working face or the panel face while the second section is displaced from the first section and then placing the second section onto the first section and pressing the placed unfolded upper shell between the working face and the panel face.