Western Wall Souvenir chips

Devarim (12:3-4) 3. And you shall overthrow their altars, and break their pillars, and burn their Asherim with fire; and you shall cut down the carved images of their gods, and destroy their names out of that place. 4. You shall not do so to the L-rd your G-d.

Rashi (Devarim 12:4) It is a prohibition addressed to one who would blot out the Name of G-d from any writing, or would pull out a stone from the altar or from the forecourt. 

Igros Moshe  (YD IV  #63.13) Question  Is it permissible to take chips from the Kosel as souvenirs?Answer  There is a clearly stated prohibition that contrary to the need to destroy idolatry. There is a reqirement not to destroy anything associated with G-d. This clearly prohibits chipping stones from the Temple or associated structures as the Rambam rules