Yes it is definitely there, as all of our patches and downloads are typically accompanied by md5 checksums to verify proper downloads.  The full man page for md5 is also available for any syntax assistance as well.  Similarly there is sha1, sha256 and rmd160 utilities as well.  But as Kip said, these are standard FreeBSD tools and not a part of RBAC or otherwise aware of the cluster architecture. 
Does the isilon have this cant see it in the binaries? Any alternatives available? Is it possible/supported to install? Our NS80 has it installed thanks
md5 checksum on isilon