Never used mossy oak gun wraps.
But back in the day, when "commercial camo" was first coming out, Bill Jordan had the foresight to make a cloth tape in trebark or whatever pattern it was.
Why I mention it was because I wrapped it all over my hunting gun at the time.
I will say that I know that isn't really the same thing and that has been 25 years ago or more now, but I didn't like it.
These days, if I am going to camo a gun, I will either use paint(s) and/or a water immersion pattern dip.