I just rebuilt mine so can say, yes, it can be taken completely apart. Now I'm trying to remember the trick to getting the push rod out as I remember it being a little stubborn. I know I had to remove the little "foot" on the bottom of the handle which just snaps out. I think it also requires removing the little ratchet pawl that moves when the rod is pushed. That, requires grinding off the peened on pin that holds the pawl in. The pin is still available and is not expensive. With the button and the above removed, the rod came out but required a little (not too much) force to remove. Most of the handle parts are still available but the push rod is showing as discontinued.
I ordered all the replacement parts from Sunset Porsche.
Also, the handle was glued on so tight on mine that I had to destroy it so I could repaint the handle body. For replacement, there are two options. Genuine Porsche has a matte finish that looks nice but doesn't match the original. Uro makes one that is a perfect match. They are about the same price. I have both here and will post a review on them when I get a chance.