Possible family members?

Today I added a sister for William Bradbury to my Ancestry.com tree - remember "Mary E." from the 1880 US Federal Census who was 18, single and living with her brother's family?  She's supposed to be his sister, so I added her and what little I knew about her, and did a quick search...and found this possible connection in the 1870 US Federal Census just 2 pages after the entry for William and his family!  It reads:

     Bradbury, Mahala age 36, female, white, Keeping House, born in Tennessee
                  James M. age 16, male, white, at home, born in Texas
                  Charly P.  age 18, male, white, at home, born in Texas, attended school this year but cannot
                                   read or write
                  Eliza J.     age 12, female, white, at home, born in Texas
                  Mary E.   age 9, female, white, at home, born in Texas
                  Sarah M. age 6, female, white, at home, born in Texas

Now, I can't prove that this is the right "Mary E. Bradbury" of course, but she's in the same area as her brother's family, and the names here correspond well with the 1860 US Census record which is presumably the correct family in Denton, TX.  It is tempting to just add this record to my Ancestry.com tree and try to find supporting evidence, which I may do, but for now I'm planning to print this out and work on it separately from my online tree.  There is already enough misinformation out there on this family!

I still have 15 min. left in my lunch hour - better get back to research!