My $.02,
I had an overlay and did not like it. I did something different with mine and that was paint it black before I put it on. I have the midnight blue mag and I could still see the crosshairs. Since I did not like, I took it off but did not look for marks since I was going to mod the front anyway.
So, Did not like but did not look to see if it left marks. Easy to install.
Before
After