It's not just the stiker but yeah it can change a call quite a bit.
Lighter tops = higher pitch
Heavier tops = deeper pitch
The denser the striker dowel the louder and higher pitch. The softer stuff is more mellow. A rosewood striker will scream on an aluminum call.
What you condition your surface with will have an effect too. Some very light grit paper (240 or lighter) will create some areas that will grap your striker better and make the call have some rasp to it. Scotch pads are good but don't get too light of a grit or you are just slicking the call over. 180 grit on a glass call is a good option. 240 grit on aluminum or copper but keep it light and don't bear down.
Most people do it but I never condition slate call surfaces. The slate just doesn't need it. I also have found that if I don't sand my striker tips when I get copper or aluminum buildup that it will actually run better.
Just some things that I have found out while producing calls.