It depends. Edwards talked of dispensations. Many Reformers will talk about dispensations. So it depends what you mean by dispensation.
Most Reformed folks unfairly stereotype what Dispensationalists believe, and are quite incorrect. That is not to say that Dispy's are correct, as they are not. But a read of Dispensationalism by Charles Ryrie will clarify some points. Let a Dispensationalist tell you what he believes and what the theory is, because it is far different from what many state.

Grace is not common.