Judging from the photo they have added a "non standard' "internal" regulator (the green wire) and grounded the remaining field terminal by removing the insulating hardware
Is your regulator, the one you are considering using, is it 69/ earlier, or 70 later?
If it's 69 earlier you should be able to remove the green/ internal regulator and just hook it up
HOWEVER IF you have done nothing to solve the "typical" old mopar bulkhead connector issues AND the voltalge drop issues from the battery--the path through the ignition switch--and to the factory regulator IT WILL overcharge.
Also a "one wire" needs to have a MUCH larger charge wire than 3 wire systems, because the sensing is on the charge wire.
