I don't think they came stock on the 86-87 TRs. But they were on the 89 TTA.
They didn't look exactly like this, but they were close. The TA ones didn't have those springs inside them. These are readily available almost everywhere.
Guy, now I know what you're looking for. As Joey noted, they did not come on the turbo regals as delivered by GM. they did come on the plug wire set for the 112 1986 Le Sabre GNs though. At least that might give you a better research point. see pics below. Parts and engine went to RCG many years ago to support Richard's Le Sabre GN that had a rod knock.