Stock components on those 520 wheels is fine and totally appropriate for loaded touring. If it's had a number of spoke failures, and you want to learn to build a wheel, this would be a fantastic place to start. Measure the existing spokes and order new ones, preferably double butted (at least on the non drive side). I like Jobst Brandst's the Bicycle Wheel as a reference, Roger Musson's ebook is also more than reasonable.
I'm not familiar with those particular Williams wheels. Do they have 32 or more spokes? If they're well built they're likely to be a reasonable touring wheel.
Tubeless compatible rims all have a distinctive center channel to aid with tire mounting, and typically a bit of an bead lock just outside of that center channel.
