Buffered with Unet?

Hello, before UNet I was working on a multiplayer game where on Start() a player he has to spawn his weapon and make it his child.

I made the spawn making a Command and ClientRpc to the server to spawn it and same with the transform but if a new player enters the game the transform.parent isn't synched.

Example:
1º the host start the game
2º the host spawn his weapon and make it his child
3º a new player enters the game
4º the new player spawn his weapon and make it his child
5º the new...

Buffered with Unet?