Get the part number 106990000 that's in stock at Numrich Gun Parts. It will work fine. Actually, it looks a little better against the grip than the newer revision/design.

From now on, be careful with the side plate. They are getting hard to come by. Most of damage to them occur when replacing the grip.

It appears, since one of the fingers is broken off, that you can simply use a punch to push the side plate out without having to remove the sear pin. You leave the punch in the frame to keep everything in place. Then, you can insert the new side plate while helping push the punch out. The sear pin will probably stay in place. You can slightly push it in from the left side of the frame so that it's flush. Then line the fingers up so you can snap the them over the groove in the sear pin. Here is how to do that. Place your left thumb tight against the fingers of the side plate while holding on to the grip/frame (be sure the fingers are still lined up with the sear pin. Then you use a plastic hammer to smack the sear pin (it will be sticking out a bit) from the right side while keep the left thumb tight against the fingers. The sear pin should "snap" right over the head of pin into the groove. Sounds a little tougher than it actually is.

You can also search for other postings that are around about this subject, especially by Fast Bolt. Good luck.

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1st Signal Brigade, RVN '70