I would do more troubleshooting than asking a guy at a stop light. It could be the cam, or the rocker arms, or the lifters, and not all of them. Have someone who knows look at it before you dive in and replace everything. Could be just a worn rocker arm or two. You need to pull the valve cover and look inside, maybe pull a rocker arm or two. The wear pattern will be visible on the rocker arm, on top where the cam rides. It does not take much wear to make some noise.

Replace the plastic cam oil tube ends while you are in there. I am sure Partshop sells the kit, it is really cheap insurance against further failure.
Good luck.