There is no reason to doubt that she was raised as a Republican and remained a Republican for all of her public life.
Mrs. Ford grew up in Grand Rapids in a day when for all practical purposes there weren't any Democrats, unless you were Polish and lived on the West Side.
Considering that Ronald Reagan ran against her husband, she's obviously not a Reagan Republican, but she does represent a major part of the old Republican Party before conservatives took it over in the 1980s. If you had asked Mrs. Ford her views about such things as capitalism, opposition to Communist expansion, and the role of the military in defending America as well as exporting American values abroad — a key issue in Gerald Ford's decision to run for Congress — you probably would have gotten answers that sound like modern Republican views.
Social issues are a whole different ball game, but we already know that.
My point was, Mrs Ford was no Reagan Republican.