Correct on both counts.

There are actually 4 different 71/4 B-body tips

Plymouth (shortest)
with resonators
without resonators

Dodge (longer than plymouth ones)
With resonators
Without resonators

The non-resonator styles have an inverted 'L' type hook that mounts to a rubber isolator in the frame. The resonator types get welded directly to the pipe and rely on the resonator mounts to support them.