I haven't updated this thread in a while, but 89P5559USA is almost ready for business again.
The new activators, Volume/Pan/Filter/3 position Q-switch arrived week before last, just as I was headed out for a week of playing music/vacation... (is there a difference?!) I only had time to open the box and admire the new parts, and remove all the installed aftermarket Bartolini equipment. Sadly, but not surprisingly, I found the control cavity was a mess too. The Volume and Pan, and Jack holes were unscathed, but the hole where the Filter pot would go had been moved almost a half-inch to the left, which didn't allow for clearance on the card. It would have to be plugged and re-drilled in it's original position. The hole that the Q-switch would go in was way oversized, and wasn't even round, so it would have to be completely redone as well.
A couple late evenings of shopwork and the repairs are complete. After some pre-fitting, including a somewhat un-nerving counterbore recess for the Q-switch, followed by brushing in a new coat of shielding paint, the control cavity is now ready to accept the new equipment.
I swear I'll post some start-to-finish pictures one day!