Item 15 lower bearing is the same back to 2013 when they switched to metric. Can be purchase separate at polaris.
Item 7 cannot be purchased separate from polaris, at least early in the season, but you can get the assault ones or the trail axys, I have a set as spares but they have the larger stud. I have seen some aftermarket but not sure if they have stock stud size or the larger size.
d8grandpa, do the assault or trail axys have 12mm studs?