Essentially, if the sear pin slides into the side of the body, then you need a grip frame with wings to hold it in place. If it screws into place, then you can use a standard frame without wings.
You can modify your body and pin so that it stays in place. Drill a tiny hole into the bottom of the body to the right or left of the sear slot, but not all the way into the breach area. Drill the hole so that it passes through the sear pin. Drill the same hole into the sear pin with the sear pin in place. Put a pin in the hole once the sear pin is mounted in the body. When you put the grip frame on the body, it will hold the small pin in place and the sear pin can't slide out to the side.
Except for the Automag in front, its usually the man behind the equipment that counts.