ALL machines need to be oiled/lubed in certain places at some point in time. But - if your user manual has no oiling instructions in it, then it is meant to be checked when it's taken in for service. A service manual will show the oiling/lube points but those are often not available to the general public. A general rule of thumb is a drop of oil where metal moves on metal.
As long as it's running nicely as you say, go ahead and use it. When you get your main machine back, you can take this one in for a service if you want to or think you might use it more often.
Cari