I am not 100% but I think they pretty much did away with these balls, due to the ball gets the load and that can result in them un screwing as loads ride and you travel!(being a round ball, rather hard to hold to get a bunch of torque on then too, , more modern one's have a flat sided base to allow some grabbing, but they still I think are no longer sold for again being known to come loose while towing)I think the 1" shank will be too large but that remains to be seen. I would suggest this type that bolts into the ball rather than the ball having a shank it helps with not having the shank sticking out the bottom where it may catch on things not a huge deal but if you can find one they work well.
you can also add something like this, which will also get the ball UP higher to keep more trailers more level and less tongue weight on the atv, plus you can use trailers that have the pin hole or other things, or can even tow ?? things with it, add a D ring clevis or??
I have one similar to this for many yrs, NOT a weld on ball like this one is, but another option for those that have interest??
ATV TEK Trio HD Multipurpose Hitch with Ball Mount : Cabela's
mine is like this one