Yes Curtis, you are exactly right in all regards
And yes when the rocker shafts start to move back and forth with the rocker they wear out the little square section seal on the end and start pissing out oil.
Same setup as the XL500S
There is another way of removing those lame locking pins if your measuring skills are precise.
Measure, centerpop and drill a fractionally smaller hole in the outside/above of the rocker box. Right above the locking pin,
then they can simply be tapped out with a pin punch. Just use some metal/bog putty to fill the hole in when all your servicing and repairs are done.
Or as you said,,,,,,,,,,,,,, find a rocker box that hasn't suffered the same failure
Yet