I just looked at the AB bare "aluminum" 9' 1" RIB
... VS AB light weight "fiberglass" VL @ 9' 6". The fiberglass one was nicer, had a flat section in the floor, and had a very DRY looking up swept bow, but it weighed about 100 pounds. The bare aluminum hull version was much less Ved, (very little bow rise), so would presumably be wetter, and had no flat section in the floor. (It looked like good performance on You Tube). The trick was that this aluminum model, in 9' 1" was ONLY 68 POUNDS! Looked like the cat's meow for small multihullers, where weight is such an issue.
Over past years, PAINTED aluminum floor models (various brands), were reputed to separate from the tubes, when the paint
to hull bond failed. I have no idea if the layer of corrosion
that would form on bare aluminum, would cause a failure of the glue bond or not? Time will tell.
They must be available, I just saw one out front of a dealer's shop in Oriental, NC.