I can't make ANY assertions about version or pedigree of the files (which came to me in 1981 when I was using a PDP-10), but they APPEAR to be from Ron Cain himself, from SRI-KL (TOPS-20): ftp://ftp.ultimate.com/pdp10/c80.tar.gz Which contains runtime files from November 1979, and compiler files dated June 1981.