I have a '95 SL500 as well and recently had all twelve cylinders rebuilt. All the recommendations I read say that you should at least repair the matching pair b/c the newly rebuilt one will put extra pressure on the older one causing it to leak eventually.
Go to Benzworld.com and look under the SL forum. Go to the third sticky. At the bottom of the page you will see a thread called "the ulimate hydrauclic cylinder site." You will find the info you are looking for.
There is a fellows from Kanas who can rebuild your cylinder for $40. He gives a 3 year guarantee. Nice guy. You will find his info there this site as well.
Hope this helps.