My operating reference for aloe ID is the "Definitive Guide" book (2011). They treat the orange-flowered plant as Aloe officinalis (an Arabian aloe) and present the history of the two plants in good detail.
I have one of the orange-flowered plants (smaller and clumpier than the standard yellow-flowered version) and I'm guessing it's a hybrid. It is definitely not sterile.
Detailed article on the subject here
http://web.archive.org/web/200...
I did not find the original but the archive seems to work.
