I think the center bath is in all models 25' and above these days. The smaller units like 22' and below have the rear corner bath. The 16' has a center wet bath.
This would apply back to the 80's models, I think.
"The further a society drifts from the truth, the more it will hate those that speak it." George Orwell
'08 34' SO, '12 Ram 2500 4X4, Big 6 cylinder sludge burner.