I have heard it called "52", "52 blocks", "52 hand", "Jailhouse Rock", and "Rock and Roll". All I have ever seen with the demos are boxing techniques mixed with various amounts of wrestling, generic martial arts, "dirty fighting"(I hate that term, since I don't think a given tactic can be dirty unless there are rules that have been aggreed upon, but it seems to fit, and "combatives".
I think I first read about it with refferences to Dennis Newsome in the 90's. Almost always refferences are made to prison and special techniques specific to those circumstances. Usually, but not always, there is a strong racial element. Everytime I see a demonstration it always strikes me as unpolished boxing with some added tricks.
This is probably true in every case that "52" comes up.
I would only temper the "fraudulant" comment with the statement that in many circumstances and cultures families or groups do seem to have "syles" specific to them. I know it goes on in the Philipines, and it was not too long ago that this practice seperated different "schools" or styles in the martial art world. Often the differences are minor, but are held to be of religious importance. Discussing the value or legitimacy of a "school", "style", or "system" is usually a great way to start a fantastic bought of purse swinging over minutia.
I suppose all one really needs to have a "system" is a lineage and history. The Japanese, Chinese, and Korean systems of martial arts that predominate in this country might make it seem like there is more to it because they come from cultures where ancester worship is the order of the day and anything and everything gets written down. Hell, look up all the different Ryu's of tea ceremony or swimming in armor that were around in feudal Japan (and thats just having a hot drink and trying not to drown).
I generally just treat whatever the hell someone self-identifies as being their style as true unless it completely strains logic.