Johnsmith96
John,
Yes, it has the square-ended caps on it.
And yes, you can use a non-magnetized brush roll on it, and there were several available:
2-059721-000, 2-159273-000 - single bristle
2-080221-000, 2-180273-000, 2-675221-000 - double bristle (no stiffeners)
2-088221-000, 2-188273-000, 2-675227-000 - double bristle (with stiffeners)
There were two other Royal upright that used this original brush roll with magnet on it: the 996 and the 9700, from 1990 to 1992, since those two models also had the green BSI (brush speed indicator) light.
As to replacement belts:
1-044260-001
~Ben