They are not threaded, the reciever splits in half and there are some grooves to help hold the stock in what ever extended position you choose.
There is a threaded hole in the railed area behind the trigger guard.
I have never adjusted mine but I think you can loosen the receiver and adjust the stock position in or out a certain amount?
I’m not looking to work in wood. I like the concept of the wire stock I just need more LOP. So looking at alternatives.