They are difficult to find and are NOT the same as the coupe. Colors are even more difficult. Check salvage yards and eBay...every now and again , a pair come up for sale from someone parting out a cabriolet. I was able to find a pair in black in very decent shape, so they can be had, but I kept my eyes open for about a year. Don't give up, but it may take awhile.
There have been other posts about being able to straighten them, as the most common issue is warping, but if yours are straight and in good shape, you may want to try refinishing them somehow. I know there are vinyl and leather dyes that may work on this material and if you're going black anyway, that will be the easiest to dye since if it doesn't come out the first time, simply apply additional coats.
Sorry I don't have any better info.
- Darryl