I have grown up in brooklyn, and still live here outside of martial arts forumsand internet I have neverheard of jailhouse rock as a style per se.Which doenst mean it doenst exist.
Growing up just about everybody practiced boxing or slapboxing to some extent, and some people developed thier own way of moving.
I could definitely see an older brother,relative or friend passing on stuff that he might have picked up in prison or from winning a few fights, but thats the natural progression of martial arts anyway before they get systematic..
I am sure the techniques are nothing special compared to muay thai, wing chun, silat, or kali, but the average guy in jail has his neck on the line and has all the time in the world to train, fight and condition himself so that is a definite edge over somebody who isnt under that kind of pressure. Even the mma guys at the worst have to only take a beating not get beat to death.