Lucy MACK Smith - Lucy Mack "Smith"

I have reason to believe that the Lucy Mack we have listed as the daughter of Solomon and Lydia Mack is not correct. I had contact with a Beckwith descendant and he believes she is the daughter of widow Grace Mack. I know Lucy married Seth Beckwith because I have seen the marriage record. It does not list the parents, only that they were married in Marlow, NH in November of 1794.
I can discuss more about this privately if anyone would like to contact me. What I have to say should not be public.
Does anyone have proof that Seth and Lucy are the parents of my 4th Great Grandfather Hubbard Beckwith?

Thanks
Cheryl Beckwith Nichols