YES. GEM can be setup to run on a stand-alone machine or on a network server. It can also be replicated to specific notebooks so that the system can still be used when people are out of the office.
It is also possible with MS SQL Server to set it up so that data is replicated between remote servers in different cities overnight - for example.
Using 3rd party software GEM can also be setup so that it can be used over the internet or an intranet.