From a logic standpoint, that might make sense, however, she could have been pregnant by another man, out of wedlock. James may have married her anyway.
If there is a will that mentions Adam as his son, or other documentation that would substantiate the theory, but the only husband is not enough.
I have run into similar issues, such as 3 generations of "Burgess Nelson"s but there is an utter lack of information showing the relationship between gen 1 and gen 2.
I suggest you work with the theory, but see if you can find more information that will help prove the point.