To the best of my memory, Jaguars of that vintage never used stainless steel beading. Beading was usually black or a matching color. As repainting was done, the beading usually wound up the same color as the body. An exception to this rule was the E Type which used stainless steel beading between the center bonnet section and the wings. Only in recent history has the importance of correct colors for the beading become an issue. When in doubt use black for an XK 120,140 or 150.