Considering adjustments needed for wheel alignment now and over time, a couple of threads doesn't make it.
My own experience has been to make my own tierods out of heavy tubes and allthread, then just slip the end of a tierod into it and weld 'er up. Same on other end. So a tierod only 10" long and cut in half would have been good enough for my application.
Only cut up and welded in those end pieces of tierod so that I could screw on my pair of 3/8" LH and RH rod ends to them, RH threads on one end, LH threads on other. (Opposite threads allow adjusting length in/out without unbolting either end.)
You need several threads into your rod ends, with room to screw in several more threads. So you can screw in/out for wheel alignments.