Yes, but not having a copy of the source code for ATT Unix stopped everyone from using BSD or any system based on BSD till 1991 (again, before then BSD was very far from being a complete OS) which is not only after the start of the GNU project, but also after the start of the Linux project, so BSD has severe shortcomings as an answer to the question that started this thread, namely, "Can you show examples of impactful open software that predates fsf and stallman?"