The OSG Client contains the tools that are used for job submission and file transfer. The Worker Node Client is insufficient in this regard. However, you can combine these in the same NFS directory (in this example /apps/osg). You can do it separately, it's just a matter of taste and what you find convenient.
pacman -get http://software.grid.iu.edu/osg-1.2:client
[note: reply YALL to "Do you want to add..."]
You may want to coordinate the fetch-crl and vdt-update-certs activities between your CE and Client/Worker Node installation directories. See the remarks in the Compute Element and Batch Scheduler Interface if you want to do this. Otherwise,
vdt-ca-manage setupca --location local --url osg
vdt-control --enable fetch-crl vdt-update-certs vdt-rotate-logs
on one system to keep the CA certs and CRLs current in the Worker Node directory.