You should be able to re-use it. You may need to disconnect a few controllers to fix the scale/positioning of the joints but it shouldn't be too much work, certainly not as much as building a rig from scratch. A lot of people I know in Maya do "scripted rigging" where they build a rig and write a script to basically…
isn't rigging most of the time scripting or writing expressions anyway? Its not that easy to get into rigging because without those scripts and workflow preparations its no fun.