If it's broke Fix it.
50,000 miles is not a lot when that Engine was designed for high mileage. I got a friend with 127,000 on his EVO and His Base Gasket just started to leak. So he's going full bore upgrades.
If you rebuild it just for Fun I would recommend either using the Old Tappet Blocks and Tappets or if you go to new I would highly recommend you use S&S Cycle Chrome Tappet Blocks, Tappets and Adjustable Quickee Pushrods. On Adjustable Pushrods when you move the Flywheel to TDC Mark to install them before you do the install take Cable ties and Lock the Foot brake down to keep the TDC Mark for front Cylinder in the Center then adjust them 4 full turns. Do the Rear Cylinder at TDC the same Way. Other wise you will hear a very bad Tapping Sound.