Yes and no: The mod's known as MIMA, and you can read about it here:
Is it too late? - MIMA Honda Insight Modified Integrated Motor Assist Tour De Sol It does more than just shutting off the assist & regen: it allows you to control them manually. Otherwise you have to go with whatever Honda's engineers programmed into the computer, which doesn't cope well with mountains, for instance. When I first got my Insight, it would drain the battery in the first couple of thousand feet of climbing, then put extra load on the engine to try to recharge while climbing the rest of the mountain. With MIMA I can shut off that unwanted load.