I put one of those slip on mag wells on my Stainless Target II. Didn't like it at all. In order for it to actually fit you need to modify the grips as shown in the pic at AZ Huskers link. I had thought that the rubber grips would compress and mold around the ears. Wrong. Big unsightly gap. Swapped it out for an Ed Brown unit. The Brown unit needed the ears filed in order to work with the SII safety, but a couple of strokes with a flat file is considerably easier than making a good job of the grip modification. Especially if you want to keep the rubber grips.
Have a GM series 1 real nice blue (early gun) put on a real nice set of Houge panels that I wanted to keep,added the Wilson mainspring housing/mag well pefect fit real nice blue,didn't have to change or modify my panels,which was what I wanted to start. Also the are a little easier to conceal than the bigger mag wells, INMHO. Just curious,AZ Heat why did you have to dremel your grips?