The roller bearings for the mainshaft output on the right side are very study. They are available in stock and two over-size dimensions.
It is not unheard of to leave a roller out to get the mainshaft to fit. It is far better to hone the outer race and use the proper rollers to get everything snug.
The Iron Sportster mainshaft is a triumph of engineering. The general design has sustained from 1952 to 1984. There were teething problems in the early K-model, but they were all cured by 1957 with the introduction of the Sportster.
Bags of rollers are cheap. You need 23 of them to fill the race.