RDA-trained PCC catalogers encountering a name authority record (NAR) with this 667 field should evaluate the 1XX field, and the remainder of the authority record. If the evaluation determines that the existing 1XX field can be used under RDA as given, the cataloger should remove the 667 field, add any additional non-heading fields, and re-code the record to RDA. If the evaluation determines that the existing 1XX needs to be updated to be made acceptable for use under RDA, the cataloger should revise the heading, make a reference from the former heading when applicable, remove the 667 field, add any additional non-heading fields of their choosing, and re-code the record to RDA. "
I interpret the instructions that it is better to retain a 1xx if the form of the name is justified in a 670. There certainly are works with "by George Fraser Black". I think it would have been better to have added a second 670 with the other form from the t.p. but can understand why the cataloger did not add one.