I have seen several 4" blued .38 cal. service sixes with something red on the front sight at shows and one on GB. It is not neatly done and on one it was very thick and hard. I tried to scrape some off with my thumbnail but it is very tough and none came off. Wondering if it is epoxy and how to remove it if I find one in nice condition. I passed on one lately in decent shape at a good price because of this. Has anyone seen one like this and know what it is? This is not an insert in the sight.