No, you're correct. It is no longer being manufactured, similar to freon but you can still buy brand new halon extinguishers and the FAA still recommends them for aircraft. We just took delivery of a new airplane a couple months ago and it came standard with a halon extinguisher - but you can buy them for any application.
One manufacturer says this about the ban:
<span style="font-style: italic">Because Halon is a CFC, the production of Halon ceased on January 1, 1994, under the Clean Air Act. There is no cost-effective means of safely and effectively disposing of the Halon that has already been produced, therefore recycling and reusing the existing supply intelligently and responsibly to protect lives and property is the best solution.
The EPA recognizes that that Halon remains the most effective "clean" extinguishing agent available, despite its ozone depleting potential, and there are no federal or state regulations prohibiting the buying, selling or use of Halon extinguishers. All Halon available now is recycled so it is an environmentally responsible choice.</span>
There are also halon-like products on the market like "halotron" that are more environmentally friendly. The only immediate drawback is halotron requires roughly twice the amount of agent that halon does to do the same job. Size/weight isn't a huge issue for shop/automotive situations though and the overall effectiveness and cleanliness is still far better than dry powder.