I would not engrave anything, in case one of my heirs fell on hard times and had to sell it. You never know what will be a future collectors item, so why ruin the value? A nice handwritten note given with the gun should be just as good. As for daughters, sure, why not leave them one? As far as the grandson goes, well, lets just say kids don't always end up the same as they are raised. :wink:
Myself, I think I would want to be buried with my semi-autos, then the grand-kids will know where to get one if they are totally banned. :-D