i tried filling mine in with the same JB Weld i used to fill in the 4 old trigger holes. It's better, but something about the way they did it, it's almost like it's raised, not etched in. it looks better than before, and is not nearly as noticeable, but if you're looking for it you can see it.
I may go back and try it again, if i get bored one day, but i'd probably try grinding in flat first and then fill it in.