Maybe my memory is faulty, but I seem to recall the BHJ I installed about 15 years back, was a solid steel unit. The BHJ has no insulator between the outer shell and inner shell. That picture looks like a stock balancer. Someone step in here and verify?
So it is. Guess its been too long since I've had to deal with replacing a balancer.pix in supercoupe performance show that rubber ring.
https://www.supercoupeperformance.com/bhj-harmonic-balancer-for-89-93-sc-xr7-739