Karl,
A magazine safety is a flat bar that is attached under the side plate. It protrudes trough a notch cut in the top leading edge of the left grip making a 90 degree bend in behind the trigger to form a trigger stop when the magazine is removed. Most, if still present (rare) will be clipped off at the 90 degree bend in order to deactivate them.
If it has been completely removed, there will be a notch cut in the top leading edge of the left grip( if the grips are original). And there will be a 1/4" hole drilled in the frame under the side plate.
This is a sear safety..
