I had the front sight fly off of my CPX2. SCCY sent me a replacement. I don't think gluing a front sight on is a good firearm engineering practice. Sorry, SCCY. Two things I did in remounting it: (1) I heated a 6-penny nail, nailhead down, on the stovetop for a couple minutes on high. I set the new sight in place, and turned the slide over on a wood surface. Then, grasping the nail with a vice-grip pliers, I mushroomed the rear most sight pin slightly by pressing down on it with the hot nailhead. The plastic never melted, it just softened enough so the downward force mushroomed it enough to hold it securely in place like a rivet. (2) I then mixed up a dab of JB Weld glue and filled the shallow factory milled depression they allow for gluing. The factory uses a softer glue, but it obviously was inadequate. Since my first sight totally disappeared at the gun range, I wanted to make sure this didn't happen to my new sight, which I improved a bit before installing.

- Sight install
Not especially fond of the factory white, three dot system, I repainted the rear sight dots and inserted a red fiber optic into the front sight.
To do this you need to chuck a small drill bit the size of your fiber optic into a hand held pin vice. I did this with the sight off of the gun. I made a jig to hold the sight by drilling two small holes on the top edge of a small block of wood matching the sight's mounting pins. Then you slowly drill a hole back to front through the sight. Go slowly and constantly check your angle. You don't want to come out too high or low on the other end. Start at the rear and work towards the front. Once the hole is finished, you need a small cutting disç in a Dremel tool to surgically remove some top and sides out of the middle of the sight. This will allow the fiber optic to catch enough ambient light to function. Check my photos below.
Next you take a small lighter and mushroom one end of the fiber optic by approaching, but not touching it with the flame. You can watch plenty of YouTube videos on how to do this. Then you clip the optic fiber to size with a nail clippers, leaving just enough to mushroom the other end after you insert it. The mushroomed ends hold the optic in place. Slip it in from the rear of the sight so you can apply the flame evenly to the more accessible front end. If you mess up, just clip the optic out and try again.

- Fiber optic front view
I used Truglo .060" fiber optics I bought on Amazon. The drill bit was 1/16".

- Fiber optic install

- Fiber optic sight picture