maybe they didn't yet invent the special elbow in 53 ?
part 3707972 explicitly to NOT bend the fuel lines is listed in the 1957 parts book.

37-51 ALL, ELBOW, inverted flared tube (5/16-20 deg.) 3707972*
*NOTE: This special 20 deg. angle fitting provides for installations of part 5592627 on 1937-51 models without bending the fuel lines.

edit: i have also found this special elbow listed in the 1954 parts book
wonder why a GM service bulletin would suggest to bend the fuel lines if a special part was made so that you didn't have to bend the fuel lines