David, Fawn Grove meeting was set up as a preparative meeting under Deer Creek Monthly (of Harford County, MD) in 1792 and was laid down about 1910. Any records for the prep meeting should be contained in the meeting for its respective Monthly Meeting, so, in this case, those records should be available at Swarthmore under Deer Creek's records.
Some of the early records from Deer Creek were extracted by Henry Peden and published by Family Line. Here's the only entry I found for Mooberry within those Deer Creek records:
"On 2nd day of 7th month, 1778...Ann Mooberry, daughter of Robert and Phebe, charged with misconduct."
I'm not seeing any wills in York County for Mooberry, so chances are the family lived in northern Maryland but attended Fawn Grove Meeting as it is very close to the state border.
Though the meetinghouse is in dire need of fresh paint these days, its adjoining burial ground is well-maintained and its grass had been freshly mown when I was there a few weeks ago. I don't remember seeing any stones for Mooberry when I was there, but I'll be going back soon to photograph them all, so I'll keep an eye out for your group.