Yes... its maybe one of three things... it is natural for e36 Ms to wear a little bit faster on the rear right tire due to the limited slip diff... its not a very tight diff back there.. but it enough to notice if you absolutly work the car on a regular basis... another reason for the wear on that tire might be your rear tailing arm bushing.. might be born causing the tires to angle in a direction that promotes wear.
Is the inside of the tire wear faster?... if so.. you have camber problems... if it is very extensive... you can purchase adjustable camber arms to control the camber on the tires back there.. and prevent the excesive wear.
BTW.. its a good rule of thumb.. to maybe ever 3 months look under the car.. and inspect your bushings... every single one of them.. and make sure they have no signs of deterioration... the slightest wear can cause a bushing to fail.. causing more problems... often you cant tell if a bushing is fully failed untill you have taken it apart from the arm.... just do a good inspection.
1997 E36 M3 1990 E30 325i