well, the priveleges on nfs mounts are ALL user ID based. If you haven't specified a user you may be mounting as root. Default security specs on Solaris map root to somebody else, often "nobody."
So, you could map root to root and mount the drive as root, and make sure all your UIDs match, and then permissions would make sense on a per user basis. You could even do nfs re-sharing. Or you could map root to a user with r/w priveleges.
I don't recall if there even is syntax for mounting an nfs point as a specific user. nfs scares me. ;-)