Yes the stock rods are adjustable. But all of the aftermarket strut rods are known by the name "adjustable strut rod".
In a nutshell,
the stock strut rod is 1 piece, with a threaded nut at the end for adjustment , pushing or pulling the wheel assy depending upon what caster setting you're trying to achieve. The stock rod uses rubber (too soft)at the adjustable end some people use poly (which is too hard, dangerous).
The wheel assy moves up and down with suspension travel, but shouldnt move front to back but under hard braking and extreme handeling, it does move in many directions it shouldn't with rubber and poly. Also poly and rubber restrict the good up and down movement.
The "adjustable strut rod" is actually 3 pieces (in all the ones i've seen)
1 end mounted at the lower arm, and the other end is mounted where stock one is under the radiator, however its mounted with a heim joint (all the ones I've seen) which only allows free up and down movement of the tire assy.
There's a center section that is used to adjust to desired length and ties all 3 pieces together.
hope this answers your question.