I've never had a faceplated Toploader in my hands, so don't know if it takes any special routine to get it dismantled? The 4th gear faceplate may cause problems from the standard procedure of putting one together?? I think Jerico you have to install the input from the front and then slip the faceplate on? Only assisted on one and that was many years ago with a friend.
Working on a toploader is really not all that hard. It takes NO special tools. Yes, the biggest hurdle is getting the shift rails and detent balls back in. It does take some finesse. After decades of working on them, I actually have fun doing them.
I deal with Paul at Liberty on a regular basis with my Nash stuff. I do lots of work for local friends. Though, never a toploader. I install new dog rings and faceplates. I have three gears on my toolbox here at work right now that I did for a buddy's Nash. Paul always gave me grief about sending stuff in and letting them do it, but their turn around time can get very, very long. After getting to know me, he sends me stuff without asking. Though lately they seem to be getting a bit lacking in shipping time. Used to be here the next day. Now it can take almost a week?