Agree with you Brian, but if you want to collect a master set of 1968 Topps most master set lists include the yellow Cox and Brinkman. If you are a real OCD type like me you have to have the whole 68 MB set anyway as sort of variations to the basic 68 set

. But if you treat the two sets completely separate, which I think is legitimate, then I think you only need one copy of them. For me, I will continue to keep one copy with each set