This is worth elaborating on: no scienctific theory, historical or experimental, is "100% convincing" in the sense that we can know it to be a completely accurate model of reality. All scientific theories are held tentatively. Thus, when one says that a historical science is "not 100% convincing" it in no way reduces the stature of that science to level beneath "experimental" sciences.
In point of fact, Popper specifically opined that historical sciences are no less scientific than the experimental sciences, in that theories in either of them can satisfy the requirement of falsifiability.
In conclusion, "historical science" does not mean "less scientific" than experimental science.
Indeed. Consider:
1. In our lab experiments starting tomorrow, the speed of light tests different from what it has been. Physics (the exemplar of an experimental science) was thus wrong to assume that "c" is a constant, and the old theory must be revised.One example is of an experimental science, the other is an historical science. Either can have its theories disproved by evidence. Both are scientific.2. In some historical science (why not use evolution as an example?) new evidence shows up that reveals a previously-held notion to be incorrect, so the old theory must be revised.