Rear disc brake conversion

Did acclaim come with a rear disc brake option in 1990? Or is there another model whose rear disc brakes would interchange with 1990 acclaim? Anyone do this conversion?

after finding a replacement rear beam axle I have found there are three brake configerations. drum, disk and abs disk. apparently there are small mounting differences. the beam axle's run about $125 less the calipers. I would be a solid $200 plus labor to change out a drum to a disk rear assembly. cant really see an advantage.