Employment question: legal proofreading

[redbird]

It seems that a lot of the temporary/contract work available is for legal proofreading. There are places that advertise legal proofreading classes. What I don't know is whether (a) they teach what I'd need to know to get such a job, and (b) whether law firms would hire me given general editorial and proofreading skills, plus one of these relatively short classes (say, two four-hour sessions, with practice/homework between), and the ability to pass a proofreading test, in the absence of specific legal proofreading experience.

Does anyone reading this know, or know where I could find out? The people teaching the classes claim high success rates, but they would.