Got my keyhole plug and installed it yesterday in between storms. I made a couple modifications to the install procedure and will list some thoughts to why. Pictures attached to tell the whole story.
1. Changed out the original junk steel screw with a T15 tamper resistant stainless steel Torx, #6 size. The #6 screw fits tight in the hole, you may have to very slightly ream the hole; I used a jewelers file to do so. (Two or three strokes max.)
If you substitute the screw, consider the head size. There is a plastic extrusion on the back side of the plastic handle cover that may hit the screw and not allow the handle to fully go to its seated position. I originally notched the handle but then figured out, all I had to do is reduce the head down a bit with a belt sander to match the radius of the flange. I also rounded the head so a pair of needle nose pliers cannot grab it. Another alternative, move the hole position slightly up or down towards the corner. (See picture)
2. I wasn't excited about putting a hole in the panel where you could see it when you pulled the handle, but after many considerations and experimenting, it is the best place for the screw hole. Anywhere else and the plug may not seat well. Hence, changing to the security screw, just to add a few more moments of confusion.
3. After I installed the plug, I didn't like the look of the open hole on the door handle, so I swapped it with the passenger side plastic. Looks good this way and may detract from the casual observer, it doesn't look like it came with a keyhole. I put the driver's side handle with a plug in it on the passenger side. The plug fits OK on this side, there is plenty of room for clearance. I will probably try to get a replacement plastic for this door in the future.
4. As others have pointed out, this is not a super secure protection method, it could easily be compromised if a thief knows what they are doing. It is a deterrent for the thief that intends to jimmy the door with a key or screwdriver, and the quick open and twist with pliers to defeat the lock. Honestly, if someone wants in your truck, they can easily get in. Most thieves are looking for valuables and will look for an easy entrance with minimal noise to avoid drawing attention. This device, in my opinion, is just one more (cheap and easy) layer you can apply.
I will also be installing a "disabling" switch.
Hope this helps!