NC 501: was born as new primary routing in 1929. It ran from its parent NC 50 (now US 1-158 Businesses) in Henderson north on W. Montgomery St to Beck Ave to modern NC 39 to the Virginia State Line. Virginia did not (and still does not) have a primary route that continued on.
By 1930, NC 501 was extended as new routing south to at least NC 561 Louisburg (N. Main at Justice) and maybe down to NC 56 (Nash St now).
Because US 501 came to be, NC 501 had to go. So, in late 1934 NC 39 was assigned to it, as it mostly remains today except within Louisburg is just N. Main St and NC 39's routing has changed in Henderson.

NC 501 initial routing

NC 501 extended south

NC 501 becomes NC 39