Jim I agree with you.
344.46 Bushings.
Where a conduit enters a box, fitting, or other enclosure, a bushing shall be provided to protect the wire from abrasion unless the design of the box, fitting, or enclosure is such as to afford equivalent protection.
It seems pretty clear to me that all RMC will have bushings regardless of wire size.
The same can be said off RNC.
352.46 Bushings.
Where a conduit enters a box, fitting, or other enclosure, a bushing or adapter shall be provided to protect the wire from abrasion unless the box, fitting, or enclosure design provides equivalent protection.
and IMC
342.46 Bushings.
Where a conduit enters a box, fitting, or other enclosure, a bushing shall be provided to protect the wire from abrasion unless the design of the box, fitting, or enclosure is such as to afford equivalent protection.
I can't see how these sections could be misunderstood.