What do we know about A. floribunda bark?
In one local garden, there are three acacias within 8 metres, which all look like floribunda to me. One of them is small and clearly appears to be a sucker from one of the others, so maybe all three suckered from the same individual. The biggest one and the smallest one have smooth bark. The middle one has several stems lopped off. The new growth is smooth stemmed but the lopped stems have deeply fissured bark.
Prior to this I'd seen a few other specimens around town, some with smooth bark and some with rough bark. Now I think it's simply a matter of bark becoming fissured after perhaps about 10 years. (The big, smooth bark specimen referred to above is about 4-6 m tall so obviously more than a couple of years old.)
One negative assay so far but they are all in bursting bud at the sec so waiting 6 months might be the answer.