Your friend is right.
If the tick goes away once warmed up a bit...it is nothing to worry about. It is called 'piston slap' and a good amount of generation III small block chevy's have it.
I googled it....and I get SO many answers. The worst being a site dedicated to ripping GM apart because of it.
www.pistonslap.com
Some info is good...most is pretty biased.
I would suggest googling "Piston slap LS1" and reading up a little on it. Should give you a pretty good idea of the so-called 'problem' that is piston slap.
Personally...I think it has to do mostly with the aluminum block and the internals. They need warmed up before they are to proper size.