This is a hard one to determine the manufacture. International Harvester had a plant in St Cloud MN next to Benton county mn. In There is also a prison in St Cloud (shelby county) and back in the day prisoners made farm equipment sold under the "Minnesota" brand. The Durst gear box indicates that it was most likely not a International Harvester but a shortline manufacture. Durst is still in business today.
Back to the real question.
For Bearings just remove them and get the part number off them or take them to Napa and they will find replacements.
For the sprocket you need to figure out what chain it uses. If it is roller chain then you should be able to find the sister sprocket, measure the OD and count the teeth. From this you can determine the chain. I like McMaster Carr to ID stuff with as their website is intuitive.
Pick the number of teeth
Then pick the OD.
McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com
It will tell you what chain that the sprocket uses if its roller chain.
Then measure your shaft ID and start hunting for a replacement. YY chain X tooth ZZ ID
Also your wheels are tiny compared to what came with it. However this is not an issue as its a PTO drive unit but your ground clearance is limited.
Hope this helps.