Does XTC's Then She Appeared (1992) infringe the copyright of Badfinger's Come And Get It (1970)? Are four (4) prominent and clearly-heard notes in common between songs reason enough to instigate a copyright infringement lawsuit?

XTC's Then She Appeared (1992) is a song written and recorded almost twenty (20) years before Toby Keith's Red Solo Cup (2011). It also prominently features the 3-4-5-8 melody. The 3-4-5-8 is the opening vocal and the hook throughout the entire song. Are four (4) prominent and clearly-heard notes in common between songs reason enough to instigate a copyright infringement lawsuit? Should XTC sue Toby Keith for copyright infringement?