Your assumption is interesting that John Perrin is a son of a Samuel Perrin b.c. 1712. However, I have another theory and tend to think the few references found to Samuel Perrin are to Samuel b.c. 1675. There seems to be nothing on record in Hanover or Lunenburg, (no church records, no tithe records, no processioning records, no witnessing deeds)that substantiate the existence of a Samuel Perrin b.c. 1712. I hypothesize that the witness to Joseph Perrin's 1742 deed in Brunswick Co., VA, was Samuel Perrin, his father, who would then have been about 67 years old. If Joseph Perrin had a brother, Samuel, who went with him to Brunswick-Lunenburg-Charlotte, he should appear on the tithe lists of Lunenburg, or on some document, which he doesn't. In 1748, tithe lists show Joseph Perrin and son William, and a Samuel Perrin, presumably Joseph's son,listed in the family of Abraham Martin. This Samuel later appears on tithe lists with his father, Joseph. I am assuming by 1748 old Samuel (1675) had died.
It is interesting that during the period between 1736 and 1742, purchases by Henry Perrin and Joseph Perrin are entered in the Thomas Partridge & Co. store accounts at Hanover County, Virginia. Henry's purchases included such items as sheep shears, woman's shoes, needles, nails, paper, a knife, and other "sundry items." Joseph Perrin bought a pair of spectacles, 1 doz. "mettle buttons", a doz. pewter buttons, a reaping sickle, 1 dozen gun flints, a hunters whistle, and a slate book. I believe that Henry and Joseph Perrin were brothers. Henry Perrin remained in Hanover Co., and was the father of Isaac Perrin, who, with his descendants remained in Hanover Co. and Amelia Co. Henry Perrin may also be the father of Joseph Perrin who went to Grainger County, Tennessee. I also think Henry could have been father of your John Perrin who married Mary Baber.
Thus, ON THE BASIS OF SUPPOSITION ONLY, AND ONLY THE SCANTIEST OF EVIDENCE, we get a family tree of:(males only)
I Samuel Perrin 1675-died 1742-1748 had sons Joseph and Henry
2 Joseph Perrin c 1700-1772 (m. Rebecca _______)Had sons William, Samuel, Josephus, and George. From Hanover Co. to Brunswick Co. (later Lunenburg and later Charlotte Co.)
2a William Perrin c 1727-1783 (m. Mary Clopton). Moved from Charlotte Co. to South Carolina
2b Samuel Perrin c 1729-1784 (m. Jane ELLIS Wade)
Settled in Halifax Co. Virginia
2c Josephus Perrin 1740-1791 (m.Cassandra Clopton. Moved from Charlotte Co. to Kentucky
2d George Perrin 1744-1797 (m. Catherine Clopton). Moved from Charlotte Co. to South Carolina
3 Henry Perrin 1710-after 1782 (wife unk.,?? a Vaiden)and had sons Isaac, John, and Joseph. Stayed in Hanover Co., Virginia
3a Isaac Perrin 1736-1821 (m. Mary Bowe). Stayed in Hanover Co. Virginia
3b John Perrin 1738-d.1810-20 (m. Mary Baber). Lived in Bedford Co., Virginia and moved to Kentucky. (The naming of a son Samuel would probably have been for grandfather Samuel Perrin)
3c Joseph Perrin 1740-1808 (m. Sarah______. Moved from Hanover Co. VA to Grainger Co., Tennessee
I doubt we shall ever know for sure, unless there is a spectacular find among the charred records of Hanover County, or someone comes up with a long hidden bible. However, it's a theory!
Mary Lou Perrin Bailey