I remember having to use different flags for bzip2 (j vs y) in tar on FreeBSD vs Linux about 15 years ago so I was sure they were different, but I have an image

I remember having to use different flags for bzip2 (j vs y) in tar on FreeBSD vs Linux about 15 years ago so I was sure they were different, but I have an image of a FreeBSD 4.10 box from June 2004 and /usr/bin/tar is indeed GNU tar.