That is a good start to investigate the possibility. This will give us something to consider and try to investigate. It would even be better if you have information about her parents, brothers and sisters even aunts and uncles to see if they could be located in the Seneca Falls Area. The married aunts and sisters can be unseen by researchers who are looking for a particular last name. I like the use of genealogy to investigate because instead of one name to find information on, there is a collective family branch to look for. If you have this information, it increases the chance of finding out the answer. As I see it, though, is that you have that she married in 1841, so it would seem more appropriate that she would have signed as Mary F. Main especially as she had children.
Thank you for this material, Charles Lenhart Seneca Falls Women's Rights National Park Volunteer Genealogy researcher