Be very very aware of laws regarding the use of lasers in public. They exist and should be followed. Obviously there are penalties for noncompliance, but no one's likely to cite you. The importance is understanding the dangers of lasers simply to keep your audience safe. Find the codes/laws and read them.
EDIT: while not relevant to entertainment lasers, it's still a good primer:
http://www.repairfaq.org/sam/lasersaf.htm#saftoc
On to your question. How the heck should we know if they're
DMX controlled? That's like asking "I just bought a car, is it automatic or stick
shift?" There are certainly devices that are controlled by
DMX, but just as many aren't. Some have seperate proprietary systems altogether and if the
system is big enough, there's a seperate "
laser operator".
Your question about sync and control really depends on the answer to your first question. If they are
DMX controlled and are moving mirror fixtures as a
DMX Laser will most likely be, they should be just as easy to syncronize and control as any moving mirror
fixture.
That first question should be pretty easy to determine on your own; just look at the thing. Next, let us know the model so we can let you know what the possibilities are.