According to the canon record sheets, the Cicada does, in fact, have arms. You can even see them in every illustration and miniature of the 'mech: they're those little wing-like structures where the arms would be. They're just little damage absorbers --- very useful.
TL;DR: Cicada = not an armless 'mech
Because there are only 3 barrels and it's not spinning, that's how you know it's not a RAC The RAC is also not around in 3049 (not until 3062), nor is it announced in the official equipment list for MW:O, which has stuck to canon 100%.
It's likely they chose a multi-barrel design to show that the Ultra AC fires more quickly than a standard AC.
And the art depicting Ultras as multi-barrel isn't exactly errant: Kraken Cygnus Burrock Urbanmech IIC (in the TRO illustration but not the model - so too are the Canis and the Hunchback IIC (hard to see in this pic)) Corvis (just like the Cicada we have). These are canon illustrations and models, and each one depicts an Ultra AC as multi-barrel; plenty of others depict the Ultra as single-barrel, or at least with a jacket occluding any indication of multiple barrels.
TL;DR: the Cicada doesn't have a RAC in 3049, but having 3 barrels is perfectly fine for an Ultra AC.
I consider them "errant" because, in a proverbial ocean of canon BT art and models depicting mechs, the ones showing ultra weapons as rotary are in the minority to ones that show them as single barreled.
I'd also like to mention that there is no such thing, at least in current technology (which lore states ACs stem from), of a modern multi-barreled but non spinning/rotary weapon system, because in all honesty, from a purely technical standpoint, multiple barrels not linked to a rotary design wouldn't be a singular firearm as they surely would not share a central ammunition feed like a minigun would, and would need to be fed individually, and thus would merely be a series of seperate guns linked to a central trigger. This conflicts with lore, which states the "ultra" autocannons are merely a single weapon system with a higher rate of fire due to an upgraded loading mechanism. If that is in fact an UAC5, which I'm sure it is, it would imply an UAC5 is actually three AC5s that are linked to one trigger, which is in conflict with their descriptions.
I understand rotary weapons do not technically come into play for a few years, I'm just pointing this out more to demonstrate that I think most BattleTech art, including this Cicada redesign, is likely a case of a "lore writer" and "fluff artist" disconnect over what exactly their weapons actually are. The writers think they're fast firing autocannons, and some of the artists think they are multi-barrelled.
Edited by SnakeTheFox, 07 June 2012 - 12:56 AM.