I believe that rubber "tube", which according to the parts manual, was to help keep the long rear springs from rubbing against the shock body. They might not have been an easy fit on your Konis so the PO could have tossed them and opted for tape instead. I put a section of bicycle innertube over my rear shocks to stave off the potential of the spring to rub on my shocks. r.d. enterprises used to sell Teflon sheets with some contact cement. The sheets were treated on one side to take the glue and you would trim them to fit the size of your shock body and glue them on to keep the springs from rubbing. I don't know if they still sell them. I'm sure there are other simple solutions - PVC pipe maybe?