Was William Early's father an indentured servant?

Jennifer Kiser reports an interesting finding: In researching indentured servants who immigrated here in the mid 18th century, she has found one James Early who entered through Philadelphia. And to whom was he indentured? One Joseph Pemberton!  Could this be the original connection with our Early's and Pembertons? Col. Early's book suggests family legend indicates our first Early family immigrant was John Early from Belfast, and that James was likely his son. Circumstantial evidence suggests that James was the father of William and grandfather of John Grandison Early. However, this speculation is not well documented, so this possible connection could mean new information. It will be helpful to know if there is any connection between Joseph Pemberton and our known Pembertons.

Tom Early has suggested looking for a Grandison line as the mother of William Early, since the given  middle name of the first born (John Grandison Early) was often the mother's maiden name . In fact, on Ancestry.com one contributor suggests that James Early and Elizabeth Grandison were the parents of William, but there is no documentation and no contact for the contributor.  Perhaps just supposition,  but perhaps a couple of additional clues...