Seems like you have this taken care of with the fill port. I thought I would post the picture of the new l3560hst control cover that is drilled and tapped for a direct to tank port. # 150 in the diagram. I believe yours is a cast boss with no machining. It would take the control cover being removed to drill and tap it properly for an orb fitting.
Also my memory could be off, but I believe the weldment for the rear remotes has three bolts to hold it down. Your picture shows two. I do know the blank cover has two bolts, which may have been the confusion for the dealer installer. This could be why your control cover is wet with hydraulic fluid...
01123-50835 bolt p#