BlazeRed and/or reflective tape..
Does anyone make brightly colored slip-on rubber grips?
Your point is well taken and not only can you lose a handgun, in the woods but other equipment as well. Took one of my Grandsons to a GS and offered to buy him a hunting knife. He went right for the camo ones and I "suggested" that he would pick another one and why. He went for the blaze orang camo pattern and that was acceptable. .....
I once lost a ramrod, out of my SideLock while coming out of the woods, at night. Never found that one but after that, wrapped a strip of reflective tape around the shaft. I can see it up to 50Ft. at night, in the woods. Now then, on your glock, even though they may not make the grips or cover you want, why not wrap the grips with blasé orange duct tape with an overlay strip of reflective tape? ......
Be Safe !!!