Jacobstd;
There are many more experienced hunters than I , but in all my research, and in my finds, I have not seen an oval colonial era button. But I agree with the others, what I have seen are oval cufflinks. They still can have the small loop in the back and the loop and the way it's attached is a good way to date it. (Jewelry is hard to date accurately).
I have seen colonial buttons reshaped into ovals and squares, (I think when they tried to repair it for continued use), but you can usually tell they were made round first. Either way, very nice finds!