How rare is the Cobb with this back? http://cgi.ebay.com/1909-11-T206-Ty-Cobb-Red-Portrait-w-Lenox-back-GAI-1_W0QQitemZ120397174054QQihZ002QQcategoryZ57993QQs sPageNameZWDVWQQrdZ1QQcmdZViewItemThanks in advance...