58-60 rear bumper inner & outer braces and supports carry different part #s in the 58 & 61 parts books. 2 of the larger vendors acknowledge this by showing their products as 59-60 and a 58 repl (replacement). The 5th Edition JG does NOT call out the differences. Educate me so I can tell if the ones in my garage are 58 or 59-60. Thanks.