What you should have done (from a guy who drills a lot of holes in the wrong place);
Slightly countersink the top of the screw hole, put a screw plug in with red Loctite that is a little too long. Cut off the screw leaving about 1/16" or less above the barrel and peen the excess screw down into the counter sink. You will still have some screw sticking up, file this off flush with the barrel, sand smooth and re-blue the area with cold blue.
Here is a similar fix in a lock plate when I drilled a hole in the wrong place of the lock bolt. You have to look close to see it, the hole is about 1/8" to the rear of the bolster screw.
Slightly countersink the top of the screw hole, put a screw plug in with red Loctite that is a little too long. Cut off the screw leaving about 1/16" or less above the barrel and peen the excess screw down into the counter sink. You will still have some screw sticking up, file this off flush with the barrel, sand smooth and re-blue the area with cold blue.
Here is a similar fix in a lock plate when I drilled a hole in the wrong place of the lock bolt. You have to look close to see it, the hole is about 1/8" to the rear of the bolster screw.