Yes...BUT I would have conditions on them. Same as I had with the boys I've cared for in the past. First of all, would never buy for them when they are very young and would never outright buy if they never asked. I wouldn't buy any that looked too realistic, only obviously play ones--water guns, nerf guns, maybe a plastic dress-up sword. Any given to us as gifts would be exchanged if I didn't find it appropriate. And I would never allow any of the 'I'm going to kill you' games. It would be redirected to a water fight maybe pretending to be a knight rescuing the princess from the dragon, etc. I had a little boy who I nannied for who loved his guns, swords and role play and only because he learned it from the older children in the neighborhood. But I always made sure we played superhereos or knights with them instead. I told him I'd put them away if he spoke like that.
I think regardless of how well you try to eliminate this kind of play, it's natural for children. They will create guns out of anything, even if they have very little contact with it. Whether it be from school, tv commercials or older children in the neighbourhood. I think sheltering them from everything is unrealistic. I think it should be more about supervised & redirected play. Correcting when things become too out of hand.