Thank you all for your answers!!
I have taken a look at the gun this morning and as you already said is clearly visible that it has been reblued and that the date has been intentionally removed!

I have also talked to the owner about those chips, and he said they were there when he bought it two years ago... he only fires "home made" low power ammo, but I have recomended him to get it inspected by a professional... he will do it asap, before his next duty tour he promised....


Thank you again for all the answers!