Very astute question.Books like the Lamkin book are secondary sources, whereas will, deeds, etc. are primary sources, even though technically they come from someone else.
In my opinion one problem in genealogy is accepting something as gospel if it appears in a hard backed book.The Lamkin book cites his sources, and for the most part is candid when making guesses as we all have to do.I have seen a few instances where I did not agree with the book, but it is far better than most.
When you get into the Mayflower, as in Plymouth, MA, you are immersed in a quagmire of claims.I would be very leery.There is another factor.Yesterday in the Westmoreland courthouse I ran into a man researching the multiple arrivals of the Mayflower in Westmoreland Co., VA.It is true.I have seen several entries mentioning it.It turns out that there were multiple Mayflowers and the one that came here was definitely not the one in 1620 in Plymouth.
To make a bona fide claim you would need to start with the Hopkins and run them down.
There were Hopkins around here in the mid 17th Century:
Northumberland County Record Book 1652-58, 20, Sparacio Abstract p. 30, 3/22/1658/9. John H( ) ( ) Hopkins a witness.
Sparacio Abstracts,Northumberland County Deed and Will Abstracts 1658-1662 Orig p.66, Spar p.94, 10/21/1661, 10/21/1661WILLIAM HOPKINS “doe freely give unto JOHN GARNER halfe my land at YOACOMICO and to his heirs. executors Admrs. or assisnes for ever”.