Hoodman,
Does the little tab behind the trigger that comes out from under the grip have an extension behind the trigger that keeps the trigger from being pulled when the magazine is out of the gun, and moves out of the way to permit the trigger to be pulled when the magazine is in the gun?
If so, you have a rare, complete magazine safety device that will add a premium to the value of the gun. As Thor stated, most of these have been deactivated by clipping off the extension that goes behind the trigger.
If your Mother-in-law's gun does have a working magazine safety, and she wants to sell it, I am interested in buying it! <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />