The pedestal mount means that the rocker fulcrum bolts directly to the rocker pedestal. Modern GT-40, E7xx and most of the newer heads are like this. Easy install, just bolt then down and torque. Geometry is adjusted by shims under the fulcrum. 351C's are also stock like this.
Shaft mount rockers are just that - they are mounted on a special shaft and pivot on that. The shaft is the fulcrum. New stuff is very high end, cost big $$$. Except for older OEM stuff that came like that - the FE engines come to mind. Shaft rockers are the best, but expensive.
Stud mount is pretty common, the rocker mounts on a stud screwed into the head. OEM types typically use a self guided rocker and positive stop stud, aftermarket and hotrodders use a stud with more thread to allow for adjustment and a guide plate to keep the rocker lined up with the valve.
The typical 289 is stud mount. Here is a site to get you started on buying the rollers. http://www.thefind.com/cars/info-cams-roller-tip-rocker-arm