Are the dovetailed sights removed/installed only in one direction? That is to say, is the dovetail milled asymmetrically (wider at one side than the other)?
Pistol in question is a Kimber; stock rear sight has a set screw which I got loose without buggering it up.
New sights are Truglo TFOs.
I had a Para C-6 several years ago, and IIRC, the rear site came off right to left, and went in left to right.
I've also read that some of the first TFO rear sights were a loose fit.