Longing for travel had brought me to my old travel pictures, when I recalled there being a sub-fleet of MH 737-800s with old interiors (Blue 90s-esque recliners in J and newer black leather seats in Y). The planes do not have IFE, and seats 1A and 1C has a great amount of legroom. On my logs, 9M-MLK and 9M-MLJ are part of this sub-fleet, but after a quick Google search, websites like Airfleets such claim that the planes were delivered new 9 years ago, to my surprise.

Does anyone know the history/story behind these planes?