Didn't take photos, but it couldn't be easier...
Tools needed: Xacto knife. Jeweler size phillips-head screwdriver.
Found the lens from a seller on eBay. He even made a special listing. Search LNB8005 lens. Don't do the "buy-it-now", make an offer. He also has different powers available. I'm toying with the idea of going up to 16mm for even a narrower field of view.
There are 4 screws located on the very corners under the black matte masking on the front of the camera. Just take the xacto knife to carefully lift up one of the corners and the mask peals off. Once the 4 small phillips-head screws are exposed and removed the cover separates from the body. The cover has wires attached to the body but they're long enough to allow access to the lens without disconnecting them. The lens is glued in place where the threads meet the base. Simply slice through the glue with the xacto knife at the base and the old lens unscrews easily. Insert the new lens and power up the camera so you can screw it in to adjust the focus. The lens turns with enough resistance that I did not glue it once focus was achieved as it will not be subjected to vibration. I reused the foam ring from the original lens. Just reassemble the case in reverse order. Reattach the mask. The mask appears to stick well with the residual glue. My only concern is how well the mask will continue to adhere to the cover in the future, but I could always apply some contact cement if becomes loose.
Although I successfully connected my old 1080p camera to this new NVR, it didn't have the same look as the new cameras, or the same functionality. The NVR wouldn't keep the settings for motion and even though the frame rate for recording was set to 30fps, the display rate couldn't be adjusted and the image motion looked choppy.
Now that the original camera is back in play, everything looks and works like it should, but now I can see 3X closer with 4K resolution.