My US version Yanmar came with that separate disc/rim with lugs design, like the larger Japan-market Yanmars. I have the original discs, and Kubota rims were put on them at some point. The lugs on these rims only have two positions (plus reversing the disc) so you have more options than I do. I have mine set to maximum which is 5 ft overall width.
For the Japan home market, I think Yanmar installed one piece wheels below a certain size tractor - maybe YM2210?? - so that's what we see now on the smaller gray market Yanmars.