I know that generally the models in the late fifties and early sixties were described as Continental as a stand alone make. Indeed, I'm not even sure those models bore the Lincoln badge. This was due to them wanting to separate the high class and expensive Continental from lesser Lincoln.

What I'm not sure of is if this lasted beyond this time.

At the end of the day people will search for a Lincoln Continental as most folk are laymen on the subject. So at the end of the day it might be the best of retaining the status quo in the interests of simplicity if not accuracy.