Since you are talking about the same pistol as you were yesterday, do the forum some good and keep it in the same thread rather than starting a new one. More signal -- less noise.
Engraved? Why? Yes, it will take away from the book value of the pistol. The only engraving that is valuable is in the eye of the beholder or engraving that was factory standard or a factory option on a new gun. You can have any number of different people engrave it, but none of them will increase the value of the pistol.
On the other hand, while you got a good deal at $300 for a decent, well made and functional handgun, you don't have some ultra-limited, insanely popular and scarce collector's piece. So the truth is, you don't have a highly collectible piece who's value would be ruined by engraving, so if it's your cup of tea, go ahead, the only real loss will be the money you spend to do it.
Spending money to get it engraved will absolutely cut in to the great deal you got on it's purchase.
Aesthetics are always going to be an opinion, but IMO, engraving works on a fine double shotgun. Engraving has no place on a working defense pistol.
But don't let the "value" of the pistol stop you from doing it if that's what you really want.
