Yes they do break as I have posted above, I have seen it happpen, not just onece either.

You won't get a decent set of rollers for the price of a set of OEM rockers or a set of doctile iron adjustable rockers either for that matter. Like said above you will also need a set of push rods if you go with adjustable rockers. If you want adjustables get yourself a set of 273 rockers and a set of push rods for a engine with hydraulic lifters and adjustable rockers. OEM 273 mechanical push roda are way to long to use with hydraulic lifers.
If you are looking for wear on the rockers it is a going to be a tough call You will take off a cover and see that there is a large gap between the rocker shaft and the top of the rocker arm, this is completely normal and is that way new.
I would sure check out an see what kind of noise you are hearing. It could also be a exhaust leak.. A lot of people make this mistake.