In general, yes, unless it's locked/unavailable, which you'd unlock in the Scenario Editor and/or make available in the Scenario Editor's Research tab.
If you're talking about Spawn Points: Scenario Editor > Edit Scenario > Park tab > Edit park dimensions and guest spawn points button > Add Spawn Point button
FYI: A Spawn Point has to have a Park Entrance between it and the rest of the park -- aside from that there's little restriction on its location and you can have several (
I once put four in the center of a park ). It's a bit confusing because there are spots the GUI mislables Spawn Point as Park Entrances.
Hope that helps!