Spellings of last names, especially this far back, were very fluid. You'll see the same person's name spelled Greene, Green, Grean, it really depended on who was recording the information, and how that person believed it should be spelled. Greene or Green, in this instance is inconsequential.
The important information is that they married different men. Death records of my Lucy's children also report her born in Canaan in 1806. How can you be sure which Lucy Green was listed in the church records in 1824?