yes after i researched the model number i figured it out :oD

anyways yes the brass bushing is the softer metal so it is supposed to be the wear side.
It doesn't mean the stub shaft won't wear it will just wear alot less.
So what i would probably do at this point is see if you can get the parts supplier to measure the ID of the new roller and see if it is anywhere near what the stub shaft is before you buy any. They should be able to give you ID specs, then you can measure the stub shaft and it should only be a couple thousands smaller in size, i'd say around 3 to 5 thousands maybe? It won't be much to allow for a slip fit.
If you don't have any calipers get some digital ones to get a more accurate reading.