I attempted to tighten the existing spray arm retainer (screw), but it wouldn’t move - then broke in the next wash cycle. Luckily I was able to remove the broken screw from the base turning it with my finger inside it. I was able to easily locate the WPL parts number from the broken piece, confirm with online manual for the model number, and ordered both the retainer screw and the ring bearing - which I realized was not on for some reason.
I spoke with a couple customer service people to confirm I was on the right track - both were very helpful. The prices were a little less than other appliance parts company I checked with.
The two parts came fast and assembly took a minute, no tools needed. I saved money on repair and felt like a very accomplished Grandma.