Gary, you could round the plug over by intersecting it with a hemisphere but that would really bloat the file size. Instead, just insinuate the roundover like this.
First, your plug is a component, right? If the plugs aren't, they should be and you should make it so.
Copy (ctrl+Move) one of the plugs and move that copy away from the rest of the model. Scale this new copy of the plug component up. It doesn't matter how much but 100 would be a good number.
Open the scaled up copy for editing.
Click on the end face to select it and get the Offset tool. Click on the edge of that face and then drag in toward the center a little way. It's not critical how much but maybe about a 10th of the distance acroos the peg.
Get the Eraser tool and, while holding the Ctrl key, click on the outside edges of the end of the plug to soften them. Then change to the Shift key and click on the offset edges to hide those.
The Offset creates a limit for the softening effect. After softening the outside edges, you just hide the limiting lines.
Once you've completed this on the scaled up version of the plug, close it. then select it so it is highlighted by the blue (or yellow) bounding box and hit the Delete key to get rid of it. All the proper sized instances of the component should show the same editing and should look a bit like they are rounded over.
This method doesn't generate a bunch of extra edges and faces.
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